In a "tentative" order, U.S. Circuit Judge Richard Posner in Chicago on Thursday said each company's case should be dismissed with prejudice, meaning it cannot be brought again.
He said neither Apple nor Motorola Mobility had enough admissible evidence of damages to withstand dismissal.
Posner also said to grant injunctions against infringements "would impose costs disproportionate to the harm to the patentee and the benefit of the alleged infringement to the alleged infringer and would be contrary to the public interest."
The judge said he expects to more fully explain his reasoning in a written opinion within one week. Posner normally handles appeals, rather than cases in trial court.
Apple and Google did not immediately respond to requests for comment.
A trial, which would have been before a jury, would have been the first between the companies since Google last month bought Motorola Mobility for $12.5 billion.
It is one of many lawsuits worldwide pitting Apple, whose iPhone is the world's most popular smartphone, against Motorola Mobility, whose parent produces the Android operating system.
In 2012, the iPhone is expected to capture more than 20 percent of the global smartphone market, while 61 percent of smartphones will use the Android system, International Data Corp said on Wednesday.
Apple had sued Motorola Mobility for alleged infringements of four patents, but a May 22 ruling by Posner scuttled its damages claims on two of those patents. Motorola Mobility had sued over one patent.
Apple is based in Cupertino, California, and Google is based in Mountain View, California.
Copyright Thomson Reuters 2012