diff --git a/srsue/hdr/upper/usim.h b/srsue/hdr/upper/usim.h
index cf5a4c820..e37f58218 100644
--- a/srsue/hdr/upper/usim.h
+++ b/srsue/hdr/upper/usim.h
@@ -43,7 +43,6 @@ typedef enum{
 typedef struct{
   std::string algo;
   std::string op;
-  std::string amf;
   std::string imsi;
   std::string imei;
   std::string k;
diff --git a/srsue/src/main.cc b/srsue/src/main.cc
index 98966510c..498aacd54 100644
--- a/srsue/src/main.cc
+++ b/srsue/src/main.cc
@@ -124,7 +124,6 @@ void parse_args(all_args_t *args, int argc, char *argv[]) {
 
     ("usim.algo", bpo::value<string>(&args->usim.algo), "USIM authentication algorithm")
     ("usim.op", bpo::value<string>(&args->usim.op), "USIM operator variant")
-    ("usim.amf", bpo::value<string>(&args->usim.amf), "USIM authentication management field")
     ("usim.imsi", bpo::value<string>(&args->usim.imsi), "USIM IMSI")
     ("usim.imei", bpo::value<string>(&args->usim.imei), "USIM IMEI")
     ("usim.k", bpo::value<string>(&args->usim.k), "USIM K")
diff --git a/srsue/src/upper/usim.cc b/srsue/src/upper/usim.cc
index fe70797e3..b9f4fda0e 100644
--- a/srsue/src/upper/usim.cc
+++ b/srsue/src/upper/usim.cc
@@ -53,13 +53,6 @@ void usim::init(usim_args_t *args, srslte::log *usim_log_)
     usim_log->console("Invalid length for OP: %d should be %d", args->op.length(), 32);
   }
 
-  if(4 == args->amf.length()) {
-    str_to_hex(args->amf, amf);
-  } else {
-    usim_log->error("Invalid length for AMF: %d should be %d", args->amf.length(), 4);
-    usim_log->console("Invalid length for AMF: %d should be %d", args->amf.length(), 4);
-  }
-
   if(15 == args->imsi.length()) {
     imsi = 0;
     for(i=0; i<15; i++)
@@ -356,6 +349,11 @@ void usim::gen_auth_res_milenage( uint8_t  *rand,
   {
     sqn[i] = autn_enb[i] ^ ak[i];
   }
+  // Extract AMF from autn
+  for(int i=0;i<2;i++)
+  {
+    amf[i]=autn_enb[6+i];
+  }
 
   // Generate MAC
   security_milenage_f1( k,
@@ -431,6 +429,10 @@ void usim::gen_auth_res_xor(uint8_t  *rand,
   for(i=0;i<6;i++) {
     sqn[i] = autn_enb[i] ^ ak[i];
   }
+  // Extract AMF from autn
+  for(int i=0;i<2;i++){
+      amf[i]=autn_enb[6+i];
+  }
 
   // Generate cdout
   for(i=0; i<6; i++) {
diff --git a/srsue/test/upper/nas_test.cc b/srsue/test/upper/nas_test.cc
index f328d77df..4f4ffb687 100644
--- a/srsue/test/upper/nas_test.cc
+++ b/srsue/test/upper/nas_test.cc
@@ -117,7 +117,6 @@ int security_command_test()
 
   usim_args_t args;
   args.algo = "xor";
-  args.amf = "9001";
   args.imei = "353490069873319";
   args.imsi = "001010123456789";
   args.k = "00112233445566778899aabbccddeeff";
@@ -179,7 +178,6 @@ int mme_attach_request_test()
   srsue::usim usim;
   usim_args_t args;
   args.algo = "xor";
-  args.amf = "9001";
   args.imei = "353490069873319";
   args.imsi = "001010123456789";
   args.k = "00112233445566778899aabbccddeeff";
diff --git a/srsue/test/upper/usim_test.cc b/srsue/test/upper/usim_test.cc
index 4ac468673..bf60e124c 100644
--- a/srsue/test/upper/usim_test.cc
+++ b/srsue/test/upper/usim_test.cc
@@ -74,7 +74,6 @@ int main(int argc, char **argv)
 
   usim_args_t args;
   args.algo = "milenage";
-  args.amf = "8000";
   args.imei = "35609204079301";
   args.imsi = "208930000000001";
   args.k = "8BAF473F2F8FD09487CCCBD7097C6862";
diff --git a/srsue/ue.conf.example b/srsue/ue.conf.example
index 347822072..140662ac0 100644
--- a/srsue/ue.conf.example
+++ b/srsue/ue.conf.example
@@ -93,7 +93,6 @@ file_max_size = -1
 [usim]
 algo = xor
 op   = 63BFA50EE6523365FF14C1F45F88737D
-amf  = 9001
 k    = 00112233445566778899aabbccddeeff
 imsi = 001010123456789
 imei = 353490069873319