Performance of Colorado potato beetle,Leptinotarsa decemlineata(Say), was compared on greenhouse-grown tomatoes,Lycopersicon esculentumMill., fertilized with nitrogen rates of 0, 25, 50, or 75 mg N kg−1soil. Higher nitrogen treatments resulted in higher nitrogen concentrations in the plants, greater plant yields, and greater nitrogen uptake. The insects that developed on plants receiving more nitrogen showed significantly higher percentage survival from first instar to adult and a smaller number of insects remaining as larvae at the termination of the experiment. Higher nitrogen treatments also resulted in significantly more rapid insect development and greater pupal mass.