Ninety-eight mothers of healthy firstborn infants 0 to 6 months old were randomly assigned to listen to 10-min of infant crying or infant cooing while continuously rating subjective feelings of frustration. Participants completed pre-test measures of depressed mood, empathy, and trait anger and post-test measures of infant-related harm thoughts, negative and positive emotions, and urge to comfort and to flee. Twenty-three (23.5 %) participants endorsed unwanted thoughts of active harm (e.g., throwing, yelling at, shaking the infant). Women in the cry condition were more likely than women in the coo condition to report thoughts of harm. Women in the cry condition who endorsed thoughts of harm reported higher frustration levels over the 10 min of crying, higher levels of post-test negative emotions, and stronger urges to flee the infant but not stronger urges to comfort the infant. Trait anger and personal distress empathy predicted the occurrence of unwanted thoughts of infant harm, whereas negative mood did not. Unwanted, intrusive, infant-related thoughts of harm may be triggered by prolonged infant crying, are predicted by personal distress empathy and a tendency to experience anger, and are associated with higher frustration, negative emotions, and the urge to escape the infant.