Since the 1980s wildlife managers in the United States and Canada have expressed increasing concern about the physical threat posed by cougars (Puma concolor) to humans. We developed a conceptual framework and analyzed 386 human– cougar encounters (29 fatal attacks, 171 instances of nonfatal contact, and 186 close-threatening encounters) to provide information relevant to public safety. We conceived of human injury and death as the outcome of 4 transitions affected by different suites of factors: (1) a human encountering a cougar: (2) given an encounter, odds that the cougar would be aggressive; (3) given aggression, odds that the cougar would attack; and (4) given an attack, odds that the human would die. We developed multivariable logistic regression models to explain variation in odds at transitions three and four using variables pertaining to characteristics of involved people and cougars. Young (≤2.5 years) or unhealthy (by weight, condition, or disease) cougars were more likely than any others to be involved in close (typically m) encounters that threatened the involved person. Of cougars in close encounters, females were more likely than males to attack, and of attacking animals, adults were more likely than juveniles to kill the victim (32% versus 9% fatality, respectively). During close encounters, victims who used a weapon killed the involved cougar in 82% of cases. Other mitigating behaviors (e.g., yelling, backing away, throwing objects, increasing stature) also substantially lessened odds of attack. People who were moving quickly or erratically when an encounter happened (running, playing, skiing, snowshoeing, biking, ATV-riding) were more likely to be attacked and killed compared to people who were less active (25% versus 8% fatality). Children (≤10 years) were more likely than single adults to be attacked, but intervention by people of any age reduced odds of a child’s death by 4.6×. Overall, cougar attacks on people in Canada and the United States were rare (currently 4 to 6/year) compared to attacks by large felids and wolves (Canis lupus) in Africa and Asia (hundreds to thousands/year).