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One hundred ninety-four prey from 31 Northern Pygmy-Owls (Claucidium gnoma) and 388 prey from 23 Northern Saw-whet Owls (Aegolius acadicus) were compared. Thirty-six percent of the pygmy-owl's prey was birds, whereas, 98.0% of the saw-whet owl's prey was small mammals, particularly voles. Food niche breadth and dietary evenness was 10.6 and 0.69 for pygmy-owls vs 3.3 and 0.89 for saw-whet Owls. Body mass of prey killed by both species was about 38 g. Dietary overlap between these two owl species was 37.0%, indicating that they fed on different prey assemblages. Received 4 April 1995, accepted 28 Aug. 1995., Northern Pygmy-Owls (Glaucidium gnoma) and Northern Saw-whet Owls (Aegolius acadicus) overlap throughout much of their range in the western United States (AOU 1983). The natural history of Northern Pygmy-Owls is [...]