The purposes of this study were to explore perceived occupational stress and related factors in public health nurses (PHNs). A convenient sampling method was used to recruit the subjects. Seven out of 12 district health centers in Taipei City and all 11 district health centers in Kaohsiung City agreed to participate in this study. Of the 171 PHNs invited to participate, 167 (97.7%) completed all mailing questionnaires. Findings showed that (1) the major sources of occupational stress in PHNs were personal responsibility and workloads, and (2) PHNs with younger age, shorter length of current working experience, longer past clinical experience, higher level of education, and less pre-job or on-job continuous education perceived more occupational stress. The findings indicate that it is necessary to develop stress-alleviating programs to reduce occupational stress in PHNs. Designing a systematic in-service training program to enhance working competency and performance of PHNs is also suggested.