Today's decision is initial, with a final decision from a six-member commission set to be delivered in November.
"S3 Graphics is pleased to win this portion of the ITC investigation," S3 Graphics CEO Dr. Ken Weng said in a statement.
An Apple representative did not immediately respond to a request for comment.
S3 Graphics, a Fremont, Calif.-based graphic chipmaker, filed its complaint against Apple in May of last year, claiming that Apple's Mac desktop and laptop computers, along with the iPhone, iPod Touch, iPad, and some software were infringing on patents it holds.
A win for S3 Graphics could result in an exclusion order to keep Apple from importing and selling hardware and software that infringes on the company's patents within the United States.
ITC judge James Gildea found Apple to be infringing on a single claim from United States Patent No. 6,683,978 and two claims from United States Patent No. 6,658,146.
S3 licenses its texture compression technology to companies such as Microsoft, Sony, and Nintendo.
This is Apple's second dealing with the ITC this in the past two days. The ITC yesterday wasin a patent infringement case against both Apple and Research In Motion from Eastman Kodak. The ITC said the final decision in that case would be delivered in late August.