Oviposition behavior is a plastic trait that can be affected by a variety of physical factors and chemical cues. The effects of water color and three chemical compounds on the oviposition behavior of Culex pipiens pallens (Diptera: Culicidae) females were studied under laboratory conditions. Solutions of methylene blue (50 mg/L) and brilliant blue (50 mg/L and 200 mg/L) attracted significantly more gravid C. pipiens pallens females than did the distilled water control. Among the three chemical compounds tested, only 0.1 mg/L acetic acid solution showed significantly greater oviposition attraction activity than the control solutions of distilled water or acetone (25 mg/L) in water. A mixture of 25 mg/L methylene blue plus 0.05 mg/L acetic acid attracted significantly more gravid females to lay eggs than did distilled water, methylene blue solutions alone, or acetic acid solutions alone. A solution of 25 mg/L methylene blue and 0.05 mg/L acetic acid might have potential for use in traps for monitoring population densities of C. pipiens pallens.