The response of ten triticale (X Triticosecale ex Wittm. A. Camus) genotypes to water deficit was investigated by withholding water at the booting stage under greenhouse conditions. Total water potential (ψ) and osmotic potential (π) were measured and used to estimate osmotic adjustment (OA). Variation was observed in OA among the genotypes. The two wheat cultivars showed high OA as expected; moreover many of the triticale cultivars appeared to respond similarly to the wheat cultivars. Linear regressions of relative water content versus π for the cultivars showed significant differences in slope (P < 0.0001). Differences in grain yield and yield components were significant between genotypes (P < 0.001). There was a significant and negative correlation between OA and sterile tiller number (P < 0.05, r²= 0.40). OA may, therefore, be a factor in improving seed set when triticale is stressed at this stage.