diff --git a/src/lhisp-oauth-client.ts b/src/lhisp-oauth-client.ts
index 213d8b4..4f60aef 100644
--- a/src/lhisp-oauth-client.ts
+++ b/src/lhisp-oauth-client.ts
@@ -1,6 +1,6 @@
 import qs from "querystring";
 import https from "https";
-import axios, { AxiosRequestConfig } from "axios";
+import axios, { AxiosHeaders, AxiosRequestConfig } from "axios";
 import {
   AccessToken,
   ContentType,
@@ -24,7 +24,7 @@ export class LhispOauthClient<iAccessToken extends AccessToken = AccessToken> {
   protected certificado?: string | Buffer;
   protected senhaCertificado?: string;
   protected authScope?: string;
-  protected headers?: Headers;
+  protected headers?: AxiosHeaders;
   protected grantType?: string;
   protected agent: https.Agent;
   protected accessToken?: iAccessToken;
@@ -47,7 +47,7 @@ export class LhispOauthClient<iAccessToken extends AccessToken = AccessToken> {
     }
 
     this.certificado = params.certificado;
-    this.headers = (params.headers ? params.headers : {}) as any as Headers;
+    this.headers = (params.headers ? params.headers : {}) as any as AxiosHeaders;
     this.apiUrl = params.apiUrl;
     this.authUrl = params.authUrl;
     this.authScope = params.authScope;
@@ -144,9 +144,10 @@ export class LhispOauthClient<iAccessToken extends AccessToken = AccessToken> {
     try {
       await this.getAccessToken();
 
-      let headers = {
+      const headers = {
         "Content-Type": contentType,
         [this.tokenHeaderName]: this.getAuthToken(),
+        ...(this.headers || {}),
       };
 
       const response = await axios.request<ResponseType>({