The aim of this study was to determine whether methionine, lysine, choline, or sulfur supplementation ameliorates adverse effects on laying performance and egg quality resulting from inclusion of a high level of common vetch seed (CVS) into diets of hens. Lohman layers, 30 wk of age as 6 replicate cages of 4 hens, were allocated randomly to receive basal diets containing either 12% soybean meal (B) or 22% CVS (BCVS) and diets BCVS plus 0.57% methionine, 0.66% lysine, 0.47% choline, or 0.05% sulfur for 98 d. Feed intake (FI) and egg production (EP) were recorded daily; egg weight (EW) was measured biweekly; and BW was measured monthly. A sample of 12 eggs from each experimental group was collected every month to evaluate egg quality. Inclusion of CVS into the basal diet caused 7.8, 11.6, 18.7, and 4.5% reductions in BW, FI, EP, and EW and 16.4% elevation in feed conversion ratio (FCR). The dietary supplementations did not alleviate depressions in BW, FI, and EW. As compared with hens fed diet BCVS, methionine and choline supplementations partially reduced the adverse effects of CVS on EP (6.2 and 2.9% increases) and FCR (7.4 and 6.6% decreases). The effects of treatments on egg quality were variable. In summary, a high level of CVS adversely affected laying performance and egg quality in peak producing hens. Partial improvements in these parameters by methionine and choline supplementations may suggest that the adverse effects of CVS could be linked to interference with methyl donor metabolism. ©2005 Poultry Science Association, Inc.