An experiment was conducted to investigate the effects of triticale in laying hen diets when used alone or in combination with maize or wheat, and with or without enzyme supplementation on hen performance, egg quality, viscosity of feed and digesta, organ weights and digestive system traits. The trial was based on a 4 (diet types; 600 g wheat (W), 600 g triticale (T), 330 g maize (M) + 300 g T and 300 g W + 300 g T kg(-1)) x 2 (enzyme levels; 0 and 1 g xylanase-based enzyme kg(-1)) factorial arrangement of treatments. Ninety-six 27-week-old Babcock B-380 laying hens were allocated to eight dietary treatments for a period of 16 weeks. Diets were iso-nitrogenous, iso-caloric and in mash form. There were no significant effects of diet type, enzyme supplementation, and diet type by enzyme supplementation interaction on hen performance (P > 0.05). Incidence of dirty eggs and thickness of eggshell also were not significantly affected by dietary treatments (P > 0.05). Eggshell breaking strength was lower in W and W/T diets than that of T and M/T diets (P < 0.05). Enzyme supplementation to T and W/T diets improved egg yolk colour significantly (P < 0.05). Extract viscosity of T diet was higher than that of other treatments (P < 0.05), and enzyme supplementation reduced extract viscosity values of experimental diets except for M/T diet (P < 0.05). Enzyme supplementation to W, T and M/T diets reduced intestinal gut viscosity (P < 0.05). Relative liver weight, however, was increased by enzyme supplementation (P < 0.05). Relative weights of heart, pancreas, crop, proventriculus, gizzard, caecum and colonic-rectum and length or relative length of small intestine were not affected by diet type or enzyme supplementation (P > 0.05). A significant interaction (P < 0.01) between diet type and enzyme supplementation was observed in the small intestine relative weight, which was reduced when enzymes were added to W or W/T diets. Experimental results demonstrated that triticale can be substituted for wheat in layer diets at 300 or 600 g kg(-1) dietary inclusion levels without any adverse effect on hen performance or egg quality except for egg yolk colour. (C) 2003 Elsevier Science B.V. All rights reserved.