The developmental effect of altered 5-HT and NE levels is a subject that requires more attention, especially when considering the increased demand for antidepressive dual reuptake inhibitors. Serotonin and norepinephrine are bioamines that differentially influence the nervous tissue growth. This study investigated the somatic maturation and the ontogeny of reflexes in neonate rats treated from the 1st to the 21st postnatal day (PND) with clomipramine (20 mg/kg sc, daily), a potent monoamine reuptake inhibitor. Indicators of both general body growth (body weight, axis of the head and body lengths) and physical maturation (ear unfolding, auditory conduit opening, eruption of the lower incisors and eye opening) were appraised. Ontogeny of motor and sensory reflexes (righting, free-fall righting--acceleration, negative geotaxis, cliff avoidance, auditory startle response and vibrissa placing) was also observed. The results demonstrated that chronic neonatal treatment with clomipramine alters the somatic growth. However, it did not interfere with the onset time of many physical features and reflexes. These results provide insights into the consequences of dual transmitter during early development.