THE AIM OF THIS STUDY WAS TO EVALUATE THE EFFECTS OF PRECEDING CROPS AND NITROGEN RATES ON YIELD AND YIELD COMPONENTS OF CORN. THE EXPERIMENT WAS CONDUCTED AT CENTER OF AGRICULTURAL SERVICES OF BAVI, AHWAZ, IRAN DURING 2012-2013 GROWING SEASON. THE EXPERIMENTAL DESIGN WAS SPLIT PLOT ARRANGEMENT (RCBD) WITH FOUR REPLICATIONS. MAIN PLOTS WERE DIFFERENT PRECEDING CROPS, CANOLA AND WHEAT. SUBPLOTS WERE NITROGEN FERTILIZER RATES (0, 100 AND 150 KG N HA-1 AS UREA FERTILIZER). PLANT HEIGHT, STEM DIAMETER, EAR LENGTH, 1000 SEED WEIGHT, SEED WEIGHT OF EACH EAR AND SEED YIELD PARAMETERS WERE EVALUATED. RESULTS INDICATED THAT EFFECTS OF PRECEDING CROPS FOR EAR LENGTH, 1000 SEED WEIGHT, SEED WEIGHT OF EACH EAR AND SEED YIELD OF CORN WERE HIGHLY SIGNIFICANT. THE N RATES SIGNIFICANTLY AFFECTED STEM DIAMETER, 1000 SEED WEIGHT, EAR LENGTH, PLANT HEIGHT AND SEED YIELD. THERE WAS A PRECEDING CROP ´ N RATE INTERACTION FOR SEED YIELD, 1000 SEED WEIGHT AND SEED WEIGHT OF EACH EAR. THIS STUDY SUGGESTED THAT N SPECIES OF PRECEDING CROPS SIGNIFICANTLY AFFECT CORN SEED YIELD AND YIELD PARAMETERS AND CANOLA MIGHT HELP TO MAXIMIZE CORN YIELD IN A CROP ROTATION SYSTEM.