An upgraded version of Sony's AIBO ERS-110 robot, called the ERS-111, was announced on October 26th of 1999. Pre-ordering ran from November 1st to 8th of 1999. Orders for the first batch completed shipment in late December of that year. Before taxes, the ERS-111 was available for sale at 250,000 JPY, 2500.00 USD, and 2,400 EU in Japan, the United States, and Europe, respectively.

Sony faced an overwhelming worldwide demand for AIBO after the ERS-110's limited release. To satiate the demand, Sony randomly picked 10,000 orders out of the first 135,000 received, and eventually released a second batch of ERS-111s in February 2000 that were available to order with no strings attached.

While the ERS-110 and ERS-111 are nearly identical in appearance, there are some notable differences that can be used to tell them apart. Both Grey Silver and Metallic Black models of the ERS-111 have shorter tails and the bottoms of their ears have an angle on one side, while the ERS-110 has a long tail and both corners of the bottoms of the ears are rounded. The ERS-111 weighs 1.4kg by itself, and 1.6kg with the battery and Memory Stick inserted. Not including the long tail, this model is approximately 274mm long, 156mm wide, and 266mm tall.

Like its predecessor, the ERS-110, the ERS-111 is equipped with 18 degrees of freedom, a 64 Bit RISC processor, and 16 MB of RAM. It draws power from a 7.2V Lithium Ion battery (See also: Batteries) and sports a 180,000 pixel color camera. There is a sensor on top of the head and on each paw, as well as two heat sensors, an accelerometer, and a velocity sensor. The ERS-111 uses IR technology to calculate distance & drops.