diff --git a/types/n3/index.d.ts b/types/n3/index.d.ts
index dd2d5ca394..a9438616c2 100644
--- a/types/n3/index.d.ts
+++ b/types/n3/index.d.ts
@@ -156,6 +156,8 @@ export interface N3Writer {
     addQuad(subject: RDF.Term, predicate: RDF.Term, object: RDF.Term | RDF.Term[], graph?: RDF.Term, done?: () => void): void;
     addQuad(quad: RDF.Quad): void;
     addQuads(quads: RDF.Quad[]): void;
+    addPrefix(prefix: string, iri: string, done?: () => void): void;
+    addPrefixes(prefixes: Prefixes, done?: () => void): void;
     end(err?: ErrorCallback, result?: string): void;
     blank(predicate: RDF.Term, object: RDF.Term): RDF.Term;
     blank(triple: BlankTriple | RDF.Quad | BlankTriple[] | RDF.Quad[]): RDF.Term;
diff --git a/types/n3/n3-tests.ts b/types/n3/n3-tests.ts
index 367b602c8a..5d6cabdeaf 100644
--- a/types/n3/n3-tests.ts
+++ b/types/n3/n3-tests.ts
@@ -3,6 +3,28 @@ import * as RDF from "rdf-js";
 import * as fs from "fs";
 import * as stream from "stream";
 
+function test_add_prefix() {
+    const writer: N3.Writer = new N3.Writer();
+
+    writer.addPrefix('xsd', 'http://www.w3.org/2001/XMLSchema#');
+    writer.end((error, result) => {
+        console.log(result);
+    });
+}
+
+function test_add_prefixes() {
+    const writer: N3.Writer = new N3.Writer();
+
+    writer.addPrefixes({
+        freebase: N3.DataFactory.namedNode("http://rdf.freebase.com/ns/"),
+        xsd: N3.DataFactory.namedNode("http://www.w3.org/2001/XMLSchema#")
+    });
+
+    writer.end((error, result) => {
+        console.log(result);
+    });
+}
+
 function test_serialize() {
     const writer: N3.N3Writer = new N3.Writer(
         {