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Field and pot experiment were conducted in University of Agriculture, Abeokuta, to develop crop coefficients (Kc) for
kenaf. Efficiency of lysimeters and Time Domain Reflectometery (TDR) in the measurement of Crop evapotranspiration
(ETc) and the Cropwat and Instat+ models in estimating reference evapotranspiration (ETo) were evaluated. The
experiment involved three varieties of Kenaf (Ifeken 100, Cuba 108 and Tainung 2) and two water supply methods (rain-fed
and irrigation). Physiological parameters and Kc estimated during the different phenological stages of kenaf grown were
analyzed with respect to treatments using inferential statistics. The result showed that Cropwat and Instat+ were related (P
< 0.05) in their estimation of ETo. A strong positive linear relation (R2= 0.72, p < 0.05) was recorded between lysimeters
and TDR measured crop evapotranspiration both on the field and in the container experiment irrespective of variety and
water supply method. The Kc from this study were highest in mid-season (0.9 - 1.2), followed by crop development period
(0.5 - 0.8), then late period (0.3 – 0.7) and finally the initial stage (0.2 - 0.4) for all varieties of crop shown irrespective of
water supply methods. The Kc for the total growth period is estimated to ranged between 0.6 - 0.7. The Kc determined by
lysimeter were about 10% higher than the TDR during the late mid - period and the late period. The field determined Kc
were slightly higher than those in the container grown crop due to container surface area lower than the ground area for
planting of crop. The study further confirmed that variety selection of kenaf, water supply method and their interaction does
not significantly (p> 0.05) influenced crop coefficient during the trial. It could be concluded that investigating Kc provides
a scientific basis for determining the extent to which the water availability will satisfy water requirement of kenaf during
the different phenological stages.