ABSTRACTFive female students were each tested 5 days a week throughout one menstrual cycle with a 3 day overlap into the next cycle. The autonomic variables reported are: sub‐lingual temperature, heart period, diastolic blood pressure, palmar and volar conductance, salivary output, and log conductance change. These measures were taken in order to estimate autonomic factor scores (Ā).Significant menstrual phase differences in Ā scores and sub‐lingual temperature were demonstrated. The Ā score estimates an autonomic factor for an individual at a particular time; low scores represent relative sympathetic nervous system (SNS) dominance. During menses, the follicular, and the ovulatory phases, Ā scores were higher; during the luteal phase the Ā scores were lowest.It was concluded that high estrogen levels are accompanied by decreased SNS