The risk of adverse reproductive outcomes was examined among semiconductor manufacturers. Personal interviews were conducted with manufacturing workers, spouses of male manufacturers, and an internal comparison group of non-manufacturing workers. Elevated spontaneous abortion ratios were observed for females working in the "diffusion" (38.9%; relative risk = 2.18, 95% confidence interval estimate = 1.1, 3.6) and photolithographic process (31.1%; relative risk = 1.75, 95% confidence interval estimate = 0.8, 3.3). Analysis of potential confounding did not substantially alter the findings. The potential for recall bias was also assessed; although the confidence interval for the comparison of diffusion and non-manufacturing workers no longer excluded 1.0, an excess risk was still reflected. No substantive differences in other reproductive outcomes were identified. Various general health symptoms were examined and reported more frequently among manufacturers than non-exposed. These results should be viewed as tentative until studies with larger numbers and more detailed exposure data are carried out.