The characteristics of wastewaters from a fertilizer factory, producing NH3, urea, diammonium phosphate (DAP) and nitrogen-phosphorus-potassium (N-P-K) fertilizer blends, were monitored in stages for 18 months to correspond with the various stages of production of the different fertilizer minerals. Analysis of physico-chemical parameters of the various wastewater categories gave the following results: temperature, 28.0-32.5 degrees C; pH, 5.0-9.48; conductivity, 2.5-2900.0 mu mhos/cm; turbidity, 2.8-17.0 NTU; colour, 5-45 platinum cobalt units; DO, 1.4-7.0 mg/l; BOD5, 1.0-41.4 mg/l; TS, 1000-8640 mg/l; TDS, 800-7600 mg/l; TSS, 200-3480 mg/l; acidity 3.0-1000.0 mgCaCO(3)/l; alkalinity, 10-460 mgCaCO(3)/l; chloride, 249-1779 mg/l; total hardness, 0.0-20.0 mgCaCO(3)/l; salinity, 0.0-3.5 parts per thousand; calcium, 0.0-18.0 mg/l; magnesium, 0.0-0.972 mg/l; potassium, 18.0-50.0 mg/l; sulphate, 0.0-6640 mg/l; orthophosphate, 5.0-64.0 mg/l; NO3-N, 0.04-1.57 mg/l; NO2-N, 0.0-0.09 ug/l; NH3-N, 0.0-0.72 mg/l. Variable results were obtained for the total coliform and faecal coliform counts with a range from 0 to > 1100 MPN/100 mi Culturable aerobic heterotrophic bacteria populations ranged from 0.53 to 3100 x 10(3) cfu/ml. The fluctuations in these parameters were attributed to seasonal variations varying effluent volumes, due to increased production capacity of the fertilizer plant, and the type of fertilizer mineral produced. A review of the waste-treatment system in the fertilizer factory is suggested, in order to minimize the impact of the pollutant components of the effluents on the ecology of the receiving creek.