Relations between maternal depression and infant behavior, attachment and development were examined within a clinical diagnostic framework. The sample consisted of a study group of 15 infants and their mothers with depression compared to a group of 16 infants and their mothers with no diagnosable psychiatric disorders. The study group scored lower on expressive (p < .03), receptive (p < .05) and overall communication (p < .03) and coping skills (p < .03) of the Vineland and total scales (p < .05) of both developmental measures and higher on psychosocial stressor severity assessments (p < .01). More mother-infant dyads in the study group presented with relationship disorders (p < .01) with considerably lower PIR-GAS (global assessment scale for parent-infant relationship) scores (p < .001). Infants of depressed mothers were also significantly more likely to show problematic attachment behavior to their mothers (p < .01). As a factor leading to the increased risk of childhood developmental problems and psychopathology, maternal depression requires special attention during clinical assessment of infants and toddlers.