diff --git a/RF24.cpp b/RF24.cpp
index 9471583d..04dff00a 100644
--- a/RF24.cpp
+++ b/RF24.cpp
@@ -240,8 +240,8 @@ void RF24::print_address_register(const char* name, uint8_t reg, uint8_t qty)
 
 RF24::RF24(uint8_t _cepin, uint8_t _cspin):
   ce_pin(_cepin), csn_pin(_cspin), wide_band(true), p_variant(false), 
-  payload_size(32), ack_payload_available(false), dynamic_payloads_enabled(false),
-  pipe0_reading_address(0)
+  payload_size(32), address_size(5), ack_payload_available(false),
+  dynamic_payloads_enabled(false), pipe0_reading_address(0)
 {
 }
 
@@ -266,6 +266,14 @@ void RF24::setPayloadSize(uint8_t size)
 
 /****************************************************************************/
 
+void RF24::setAddressSize(uint8_t size)
+{
+  address_size = max(3,min(5,size));
+  write_register(SETUP_AW, (address_size-2) & 0x03 );
+}
+
+/****************************************************************************/
+
 uint8_t RF24::getPayloadSize(void)
 {
   return payload_size;
@@ -400,7 +408,7 @@ void RF24::startListening(void)
 
   // Restore the pipe0 adddress, if exists
   if (pipe0_reading_address)
-    write_register(RX_ADDR_P0, reinterpret_cast<const uint8_t*>(&pipe0_reading_address), 5);
+    write_register(RX_ADDR_P0, reinterpret_cast<const uint8_t*>(&pipe0_reading_address), address_size);
 
   // Flush buffers
   flush_rx();
@@ -606,8 +614,8 @@ void RF24::openWritingPipe(uint64_t value)
   // Note that AVR 8-bit uC's store this LSB first, and the NRF24L01(+)
   // expects it LSB first too, so we're good.
 
-  write_register(RX_ADDR_P0, reinterpret_cast<uint8_t*>(&value), 5);
-  write_register(TX_ADDR, reinterpret_cast<uint8_t*>(&value), 5);
+  write_register(RX_ADDR_P0, reinterpret_cast<uint8_t*>(&value), address_size);
+  write_register(TX_ADDR, reinterpret_cast<uint8_t*>(&value), address_size);
 
   const uint8_t max_payload_size = 32;
   write_register(RX_PW_P0,min(payload_size,max_payload_size));
@@ -640,7 +648,7 @@ void RF24::openReadingPipe(uint8_t child, uint64_t address)
   {
     // For pipes 2-5, only write the LSB
     if ( child < 2 )
-      write_register(pgm_read_byte(&child_pipe[child]), reinterpret_cast<const uint8_t*>(&address), 5);
+      write_register(pgm_read_byte(&child_pipe[child]), reinterpret_cast<const uint8_t*>(&address), address_size);
     else
       write_register(pgm_read_byte(&child_pipe[child]), reinterpret_cast<const uint8_t*>(&address), 1);
 
diff --git a/RF24.h b/RF24.h
index 18914f09..4baea079 100644
--- a/RF24.h
+++ b/RF24.h
@@ -50,6 +50,7 @@ class RF24
   bool wide_band; /* 2Mbs data rate in use? */
   bool p_variant; /* False for RF24L01 and true for RF24L01P */
   uint8_t payload_size; /**< Fixed size of payloads */
+  uint8_t address_size; /**< Size of hardware addresses */
   bool ack_payload_available; /**< Whether there is an ack payload waiting */
   bool dynamic_payloads_enabled; /**< Whether dynamic payloads are enabled. */ 
   uint8_t ack_payload_length; /**< Dynamic size of pending ack payload. */
@@ -388,6 +389,15 @@ class RF24
    */
   void setPayloadSize(uint8_t size);
 
+  /**
+   * Set Hardware Address Size
+   *
+   * Set to either 3, 4 or 5 bytes. Default is 5.
+   *
+   * @param size The number of bytes in the payload
+   */
+  void setAddressSize(uint8_t size);
+
   /**
    * Get Static Payload Size
    *