Of 45 amides synthesized from five alicyclic carboxylic acids and nine heterocyclic amines, 39 were class 5 repellents (effectiveness >21 days) against Aedes aegypti (L.) or Anopheles quadrimaculatus Say when tested on cloth and are considered promising mosquito repellents. Eighteen of the amides were highly effective, providing 70 or more days of protection against one or both mosquito species. The cyclohexane-carboxamides of 2-, 3-, and 4-methylpiperidine, 2-ethylpiperidine, and 2,6-dimethylpiperidine were the most effective repellents against Ae. aegypti, providing 104 days of protection. 4- (Bicyclo[2.2.1] hept - 5 - en -2 - ylcarbonyl) -2,6 - dimethylmorpholine was exceptionally effective against An. quadrimaculatus, providing 190 days of protection.