A new approach to the assessment of breast health was developed based upon continuous ambulatory recording of breast temperature for 24 hrs. A new data acquisition system consisting of a portable, multi-channel, microprocessor-based recorder worn on a belt was developed to record temperatures. Dramatic thermal fluctuations were noted during the recordings in response to multiple stimuli (physiological, behavioral, environmental). Specific algorithms and software programs were developed to process the thermobiologic and chronobiologic information. Data processing was fully automatic and included an examination report indicating a score and a chronothermodynamic class for each of the five areas examined on each breast. The preliminary clinical studies have concerned more than 450 patients with healthy or diseased breasts.