The purpose of this research was to discover how women make a self-diagnosis of pregnancy and given that diagnosis, how they make decisions regarding prenatal care. The self-diagnosis portion of the study is presented here. Transcriptions from interviews with 30 pregnant and postpartum women were analyzed using the constant comparative method. The resultant model conceptualizes the phases of pregnancy self-diagnosis and includes descriptive data concerning diagnostic indicators of pregnancy. Implications for further development of the concept of self-diagnosis and its relevance to nursing practice are discussed. Plans for a follow-up study testing the model of self-diagnosis of pregnancy are also presented.