This paper examines the effects of chronic exposure to the trace elements, lead and cadmium, on the central nervous system of F1 generation Wistar rats. Both the parental and F1 generation received treatments consisting of two levels of lead (5 or 50 ppm), two levels of cadmium (0.1 or 5 ppm), and two combined dosages (5 ppm lead and 0.1 ppm cadmium, or 50 ppm lead and 5 ppm cadmium). Treatments were administered in buffered drinking water. Behavioral changes, as measured by locomotor activity, were found to be both dose and age dependent. Changes in brain biogenic amino levels were also both dose and age dependent. In general, lead treatment caused decreases in blood aminolevulinio acid dehydrotase while cadmium caused increases in brain acetylcholinesterase and monamine oxidase. This study suggests that both behavior and biogenic amine level changes in discrete brain areas can occur as early as 30 days of age and these changes may be sensitive signs of chronic exposure to lead and/or cadmium.