A number of arylbiurets were prepared and evaluated as antiinflammatory and analgesic agents by using the carrageenan paw edema and acetic acid stretching tests. Among them, the antiinflammatory activity of 1,3-dimethyl-5-phenylbiuret (7), 1-ethyl-3-methyl-5-phenylbiuret (11), and 1,1,3-trimethyl-5-phenylbiuret (13) were found to be more potent than phenylbutazone. The analgesic activity of 7 and of 5-(4-chlorophenyl)-1,1,3-trimethylphenylbiuret (16) is higher than that of aminopyrine.