Abstract: The Nigerian local chickens were grouped on the basis of body size and body weight into Heavy Ecotype (HE) and Light Ecotype (LE). Comparative evaluation of growth traits; Body Weight (BWT), Body Weight Gain (BWG) and Feed Conversion Ratio (FCR) at 4-weekly intervals (from 0-20 weeks) of HE, LE and their F1 crosses; HE x LE - Main Cross (MCX) and LE x HE - Reciprocal Cross (RCX) were carried out. The total of 214, 142, 190 and 185 day-old chicks of HE, LE, MCX and RCX, respectively were used for the study. The chicks in all the genetic groups were raised on deep litter pens from 0-20 weeks using standard management procedures. Data were subjected to analysis of variance. Results showed that the HE differed (p<0.05) from the LE in BWT (0-20 weeks). Crossing the HE with LE appeared to have closed the gap between HE and LE in BWT as there were no significant differences (p>0.05) between the BWT of HE and the crossbred groups as from 8-20 weeks of age. The crossbred groups quickly overcame the initial set backs resulting from maternal/sire-dam interaction effects and grew significantly heavier than the straight bred heavy and light ecotypes during the period, 12-20 weeks of age. FCR showed highly significant (p<0.001) difference among the genetic groups which indicates differences in maintenance requirements. On the whole, results of FCR showed that the local chickens are less efficient in feed utilization.