This study focuses on the questions of when and how military intervention in conflicts can achieve humanitarian benefits. It uses the standard that an intervention should do more good than harm to evaluate the successes and failures. The author develops a methodology to determine the number oflives saved, as a minimalist measure. The analysis of 19 military operations in the 6 case studies of Iraq, Somalia, Bosnia, Rwanda, Kosovo and East Timor reveals both successful and unsuccessful interventions in the same locations. The study posits that an intervention's short-term effectivenessdepends primarily on six factors within the control of the intervenor, rather than factors inherent within the conflict. Political and humanitarian dimensions are combined to create a typology that compares the needs of populations suffering from conflict with an intervenor's military interventionstrategies, motives, capabilities and response time. Hypotheses derived from the model are tested in the case studies and policy implications are offered.