A comparison of host feeding behavior on chickens and humans was conducted with a Bladensburg, Maryland strain of Culex pipiens L. during 1977 and 1978. Three thousand female Cx. pipiens were tested for multiple feeding potential on chickens while 3200 Cx. pipiens were used for comparing multiple feeding preferences on chickens and humans. Data showed "opportunistic" feeding tendencies; 7.2% took the 2nd blood meal from a chicken; 4.0% from a man. It is suggested that this strain of Cx. pipiens has good vector potential for St. Louis encephalitis since, after taking bird blood, the second blood meal some-times consisted of human blood.