Technical Abstract: Pima cotton is roller ginned to minimize damage to the fiber. The US roller ginning industry has changed since 1989. The majority of gins have shifted from Arizona to California. The number of gins in the US has also fallen by nearly 50%, but those operating today have more gin stands and process cotton at nearly twice the rate. A survey was conducted to better understand how current foreign matter removal practices affect Pima cotton quality. There were very few similarities in machinery set-up for seed-cotton cleaning among gins. Most gins use one or two cylinder cleaners and an air-type lint cleaner for lint cleaning. The trend in roller ginning today is toward aggressive seed-cotton cleaning and gentle lint cleaning to limit fiber damage. Cotton property measurements taken before and after cleaning showed that, in general, cleaning machinery reduced foreign matter content in seed cotton and lint. Also, cleaning machines tended to reduce fiber length and increase neps. There was an average increase in lint value from 1.66 to 1.72 $/kg (75.5 to 78.1 ¢/lb) due to lint cleaning. This increase could not be attributed to any one type of lint-cleaning machine. No definite recommendations for foreign matter removal at US roller gins could be made, but the results emphasized the need for controlled evaluations of individual cleaning machines.