Abstract: This study investigated the relationships between body condition, seminal plasma composition and physical parameters of Salmo trutta fario in order to find out biomarkers for semen quality. Seminal plasma contained 79.0±15.15 mmol L-1 Na+, 46.8±9.84 mmol L-1 K+, 3.5±0.67 mg dL-1 Ca+4, 3.5±0.80 (mEqL-1 Mg++, 14.8±5.15 mgdl glucose, 3.0±9.42 g dL-1 protein, 19.2±18.57 mg dL-1 cholesterol, 5.4±3.17 mg dL-1 triglyceride and 3.0±9.42 mg dL-1 urea. Semen volume was 3.90±1.48 mL, spermatozoa motility 81.0±10.74%, duration of spermatozoa movement 97.4±15.23 s., spermatozoa density 9432.5±3762.07 x109 mL-1, total spermatozoa density 35102.4±19137.5 x109 and semen pH 7.6±0.39. There were significant positive correlations between weight and protein (r=0.752, p<0.05), weight and cholesterol (r = 0.832, p<0.01), length and protein (r = 0.729, p<0.05), length and cholesterol (r = 0.761, p<0.05), volume and cholesterol (r = 0.667, p<0.05), volume and urea (r = 0.753, p<0.05), density and total density (r = 0.704, p<0.05), total density and calcium (r = 0.676, p<0.05), Na+ and K+ (r = 0.822, p<0.01), Mg++ and protein (r = 0.932, p<0.01), protein and cholesterol (r = 0.882, p<0.01), cholesterol and urea (r = 0.885, p<0.01). Significantly negative correlation were found between K+ and pH (r = -0.891, p<0.01), Ca++ and pH (r = -695, p<0.05) and Na+ and urea (r = -0.798, p<0.01). The phenotypic correlation between body weight and length was found highly significant (r = 0.984, p<0.01).