WASHINGTON — The Federal Trade Commission Thursday handed Google a major victory by declaring, after an investigation of nearly two years, that the company had not violated antitrust or anticompetition statutes in the way it arranges its Web search results.

Google can now continue to present search results that highlight its own services. The decision also enables Google to avoid a costly and lengthy legal war of attrition like the antitrust battle that Microsoft waged in the 1990s.

Google, which attracts 70 percent of all search queries in the United States, has used its search business, which generates billions of dollars in profit annually from advertising, to expand into businesses that include maps, restaurant reviews and travel bookings. Competitors worry that the FTC’s decision will allow Google to continue to make inroads at their expense.

The decision sets up a potential conflict with European officials, who are working with Google to resolve similar concerns about the way the company operates its search engine in Europe, where it is even more dominant than in the United States.

Web search has become vital to the success of many businesses. Being ranked higher in search results can mean a great deal more traffic and revenue; being ranked lower can hurt both. Google has long claimed that it uses a neutral algorithm for search queries, something that competitors disputed.

But Jon Leibowitz, chairman of the FTC, said that “While not everything Google did was beneficial, on balance we did not believe that the evidence supported an FTC challenge to this aspect of Google’s business under American law.”

The five-member commission voted unanimously to close its investigation without bringing charges. The FTC said it found that Google’s practices improved its search results for the benefit of users and that “any negative impact on actual or perceived competitors was incidental.”

Google did agree to make some minor changes to its search practices related to search advertising. The FTC said those commitments were enforceable if the company violated them, but the agreement avoided a formal consent decree or litigation, weapons that the FTC had available.

The commission also found that Google misused its broad patents on cellphone technology, and it ordered Google to make that technology available to rivals. Google also agreed to stop taking its rivals’ content for use in its specialized search results, and agreed to stop restrictions preventing small businesses from advertising on competing search platforms.

Last year, some FTC staff members pushed hard in reports to the commission that the company’s actions constituted “unfair methods of competition,” an area that, like that of antitrust, is policed by the FTC.