diff --git a/blockdag/dag_test.go b/blockdag/dag_test.go
index 57a867d2a..31f158a1b 100644
--- a/blockdag/dag_test.go
+++ b/blockdag/dag_test.go
@@ -8,6 +8,8 @@ import (
 	"errors"
 	"fmt"
 	"math"
+	"os"
+	"path/filepath"
 	"reflect"
 	"strings"
 	"testing"
@@ -19,6 +21,7 @@ import (
 
 	"github.com/daglabs/btcd/dagconfig"
 	"github.com/daglabs/btcd/dagconfig/daghash"
+	"github.com/daglabs/btcd/database"
 	"github.com/daglabs/btcd/txscript"
 	"github.com/daglabs/btcd/util"
 	"github.com/daglabs/btcd/util/subnetworkid"
@@ -864,6 +867,49 @@ func testErrorThroughPatching(t *testing.T, expectedErrorMessage string, targetF
 	}
 }
 
+func TestNew(t *testing.T) {
+	// Create the root directory for test databases.
+	if !fileExists(testDbRoot) {
+		if err := os.MkdirAll(testDbRoot, 0700); err != nil {
+			t.Fatalf("unable to create test db "+
+				"root: %s", err)
+		}
+	}
+
+	dbPath := filepath.Join(testDbRoot, "TestNew")
+	_ = os.RemoveAll(dbPath)
+	db, err := database.Create(testDbType, dbPath, blockDataNet)
+	if err != nil {
+		t.Fatalf("error creating db: %s", err)
+	}
+	defer func() {
+		db.Close()
+		os.RemoveAll(dbPath)
+		os.RemoveAll(testDbRoot)
+	}()
+	config := &Config{
+		DAGParams:    &dagconfig.SimNetParams,
+		SubnetworkID: subnetworkid.SubnetworkIDSupportsAll,
+		DB:           db,
+		TimeSource:   NewMedianTime(),
+		SigCache:     txscript.NewSigCache(1000),
+	}
+	_, err = New(config)
+	if err != nil {
+		t.Fatalf("failed to create dag instance: %s", err)
+	}
+
+	config.SubnetworkID = &subnetworkid.SubnetworkID{0xff}
+	_, err = New(config)
+	expectedErrorMessage := fmt.Sprintf("Cannot start btcd with subnetwork ID %s because"+
+		" its database is already built with subnetwork ID %s. If you"+
+		" want to switch to a new database, please reset the"+
+		" database by starting btcd with --reset-db flag", config.SubnetworkID, subnetworkid.SubnetworkIDSupportsAll)
+	if err.Error() != expectedErrorMessage {
+		t.Errorf("Unexpected error. Expected error '%s' but got '%s'", expectedErrorMessage, err)
+	}
+}
+
 func TestValidateFeeTransaction(t *testing.T) {
 	params := dagconfig.SimNetParams
 	params.K = 1
diff --git a/blockdag/dagio.go b/blockdag/dagio.go
index 4fcf2477b..58bdfef4a 100644
--- a/blockdag/dagio.go
+++ b/blockdag/dagio.go
@@ -14,6 +14,7 @@ import (
 	"github.com/daglabs/btcd/dagconfig/daghash"
 	"github.com/daglabs/btcd/database"
 	"github.com/daglabs/btcd/util"
+	"github.com/daglabs/btcd/util/subnetworkid"
 	"github.com/daglabs/btcd/wire"
 )
 
@@ -57,6 +58,10 @@ var (
 	// subnetwork registry.
 	subnetworksBucketName = []byte("subnetworks")
 
+	// localSubnetworkKeyName is the name of the db key used to store the
+	// node's local subnetwork ID.
+	localSubnetworkKeyName = []byte("localsubnetworkidkey")
+
 	// byteOrder is the preferred byte order used for serializing numeric
 	// fields for storage in the database.
 	byteOrder = binary.LittleEndian
@@ -480,6 +485,10 @@ func (dag *BlockDAG) createDAGState() error {
 		if err != nil {
 			return err
 		}
+
+		if err := dbPutLocalSubnetworkID(dbTx, dag.subnetworkID); err != nil {
+			return err
+		}
 		return nil
 	})
 
@@ -489,15 +498,30 @@ func (dag *BlockDAG) createDAGState() error {
 	return nil
 }
 
+func dbPutLocalSubnetworkID(dbTx database.Tx, subnetworkID *subnetworkid.SubnetworkID) error {
+	return dbTx.Metadata().Put(localSubnetworkKeyName, subnetworkID[:])
+}
+
 // initDAGState attempts to load and initialize the DAG state from the
 // database.  When the db does not yet contain any DAG state, both it and the
 // DAG state are initialized to the genesis block.
 func (dag *BlockDAG) initDAGState() error {
-	// Determine the state of the chain database. We may need to initialize
+	// Determine the state of the DAG database. We may need to initialize
 	// everything from scratch or upgrade certain buckets.
 	var initialized bool
 	err := dag.db.View(func(dbTx database.Tx) error {
 		initialized = dbTx.Metadata().Get(dagStateKeyName) != nil
+		if initialized {
+			localSubnetworkIDBytes := dbTx.Metadata().Get(localSubnetworkKeyName)
+			localSubnetworkID := &subnetworkid.SubnetworkID{}
+			localSubnetworkID.SetBytes(localSubnetworkIDBytes)
+			if !localSubnetworkID.IsEqual(dag.subnetworkID) {
+				return fmt.Errorf("Cannot start btcd with subnetwork ID %s because"+
+					" its database is already built with subnetwork ID %s. If you"+
+					" want to switch to a new database, please reset the"+
+					" database by starting btcd with --reset-db flag", dag.subnetworkID, localSubnetworkID)
+			}
+		}
 		return nil
 	})
 	if err != nil {
diff --git a/btcd.go b/btcd.go
index bb9fadabd..26df72531 100644
--- a/btcd.go
+++ b/btcd.go
@@ -106,6 +106,14 @@ func btcdMain(serverChan chan<- *server.Server) error {
 		return nil
 	}
 
+	if cfg.ResetDatabase {
+		err := removeDatabase()
+		if err != nil {
+			btcdLog.Errorf("%s", err)
+			return err
+		}
+	}
+
 	// Load the block database.
 	db, err := loadBlockDB()
 	if err != nil {
@@ -179,6 +187,11 @@ func btcdMain(serverChan chan<- *server.Server) error {
 	return nil
 }
 
+func removeDatabase() error {
+	dbPath := blockDbPath(cfg.DbType)
+	return os.RemoveAll(dbPath)
+}
+
 // removeRegressionDB removes the existing regression test database if running
 // in regression test mode and it already exists.
 func removeRegressionDB(dbPath string) error {
diff --git a/config/config.go b/config/config.go
index af39b45c3..acb747283 100644
--- a/config/config.go
+++ b/config/config.go
@@ -140,7 +140,7 @@ type configFlags struct {
 	SimNet               bool          `long:"simnet" description:"Use the simulation test network"`
 	AddCheckpoints       []string      `long:"addcheckpoint" description:"Add a custom checkpoint.  Format: '<height>:<hash>'"`
 	DisableCheckpoints   bool          `long:"nocheckpoints" description:"Disable built-in checkpoints.  Don't do this unless you know what you're doing."`
-	DbType               string        `long:"dbtype" description:"Database backend to use for the Block Chain"`
+	DbType               string        `long:"dbtype" description:"Database backend to use for the Block DAG"`
 	Profile              string        `long:"profile" description:"Enable HTTP profiling on given port -- NOTE port must be between 1024 and 65536"`
 	CPUProfile           string        `long:"cpuprofile" description:"Write CPU profile to the specified file"`
 	DebugLevel           string        `short:"d" long:"debuglevel" description:"Logging level for all subsystems {trace, debug, info, warn, error, critical} -- You may also specify <subsystem>=<level>,<subsystem2>=<level>,... to set the log level for individual subsystems -- Use show to list available subsystems"`
@@ -167,6 +167,7 @@ type configFlags struct {
 	RelayNonStd          bool          `long:"relaynonstd" description:"Relay non-standard transactions regardless of the default settings for the active network."`
 	RejectNonStd         bool          `long:"rejectnonstd" description:"Reject non-standard transactions regardless of the default settings for the active network."`
 	Subnetwork           string        `long:"subnetwork" description:"If subnetwork ID != 0, than node will request and process only payloads from specified subnetwork. And if subnetwork ID is 0, than payloads of all subnetworks are processed. Subnetworks with IDs 3 through 255 are reserved for future use and are currently not allowed."`
+	ResetDatabase        bool          `long:"reset-db" description:"Reset database before starting node. It's needed when switching between subnetworks."`
 }
 
 // Config defines the configuration options for btcd.