This study was designed to determine the effects of a single dose of dietary Cysteamine (Cys) on growth performance parameters, meat properties and laying performance, hatchability, plasma glucose, cholesterol, and sex hormone levels of quails. For this purpose, two separated animal experiments have designed as growth period Trial 1 (T1) and laying period Trial 2 (T2) and experiments have conducted one after another. Trial 1 (T1): A total of two hundred, 1-day old quail (Coturnix coturnix japonica) chicks were randomly allocated to 1 of two treatment groups with 5 replicates, either a control group (basal diet) or a treatment group that contained 90 mg Cys per kg basal diet. During the 5-weekexperimentalperiod, the performance data regarding the growth period were collected. At the end of T1, a total of 30 quail were slaughtered, and the color values, pH, and meat macronutrients were determined in breast meat.Data from T1 showed that the inclusion of 90 mg Cys in the diet affectedneither growth performance nor breast meat parameters of quail. Trial 2 (T2): At the end of T1, 40 from each treatment and a total of 80, six-week-old quail were selected randomly to be used in the laying period experiment and allocated to two dietary treatment groups. Forty quails from the control group of T1 were fed with a laying period basal diet. Forty quails from the Cys group of T1 were fed with a laying period diet that contained Cys (90 mg/kg basal diet). During the 10-week laying trial egg production and hatching performance data collected. At the end of the trial, a total of 20 quails were sacrificed and plasma glucose, cholesterol, and sex hormone levels were detected. Results of T2 displayed that 90 mg /kg feed dietary Cysincreased egg mass (P< 0.05), however, it was ineffective on other laying and hatching performance parameters. Whereas plasma glucose level was not altered, plasma cholesterol level significantly decreased with the presence of Cys in the diet (P< 0.05). Moreover, dietary Cys significantly increased plasma sex hormones levels in both sexes. In conclusion, 90 mg dietary Cys did not show any improvement or depressing effect on the growth, laying, or hatching performance of quails however, its cholesterol-lowering impact and boosting effects on plasma sex hormones are noteworthy.