[(Cycloalkylmethyl)phenyl]acetic acid derivatives and relatedcompounds were synthesized to test their antiinflammatory and analgesic activities. Some of the compounds in this series were found to have good activity in the carrageenan edema test. Among them, sodium 2-[4-[(2-oxocyclopentyl)methyl] phenyl]propionate dihydrate (15) and 2-[4-[(2-oxocyclohexylidene)methyl]phenyl]propionic acid (13b) showed potent analgesic