The introduction of a national health care system in Canada has resulted in regular and increasing conflict between the medical profession, government and other political actors. The present longitudinal study utilizes a stressor-strain framework to understand physician militancy in Canada. Data were collected from 1298 men and women physicians at two points in time separated by 4-5 years using questionnaires completed anonymously. Four groups of predictor variables identified in previous research were considered: individual demographic characteristics, practice characteristics, work stressors and work and professional satisfactions. Empirical support for the model was found. Each panel of predictor variables had significant and unique relationships with most measures of physician militancy measured 4-5 years later.