The introduction of powdery mildew-resistant squash cultivars has offered the grower a more efficient approach to producing a high-quality crop for market and managing this disease. It is an annual problem in Iowa; indeed, in some years it has the potential to ruin the cucurbit crops if not controlled. This trial was established to provide an unbiased performance evaluation of cultivars with reported resistance/tolerance to powdery mildew and to generate information useful to growers for selecting the right cultivar for their marketing objectives.