The relationship of adolescent mothers' knowledge of infant development and perceptions of infant behavior to stress experienced during pregnancy were examined using a comparison group of adults of similar marital status. Relationships with maternal age across groups also were examined. Adolescents underestimated developmental rate and perceived some infant behaviors less optimally, but did not differ in levels of stress. Stress was related to several parenting subscores. Some support for a linear relationship with maternal age was found. Results suggest the need for further research to determine how level of maturity affects translation of knowledge into maternal action.