The narrow clawed crayfish, Astacus leptodactylus Eschscholtz, 1823 is the only native freshwater crayfish species of Turkey. Crayfish are standard test organism in the OECD Testing Guidelines and has importance in ecotoxicological studies/environmental monitoring programs due to its critical position in the food web and lake bottom feeding habits. Crayfish (males and non-ovigerous females; 9.77 +/- 0.66 cm total length, 24.82 +/- 2.96 g weight) hemolymph were collected and analyzed for total hemocyte count and hemolymph were biochemical parameters reference range for the species by autoanalyzer. Animals were maintained under laboratory conditions for 2 weeks before measurements. All biochemical parameters, except chloride and lactic acid, showed normal distribution when tested for normality with the using Kolmogorov Smirnov (K-S) test. The means and standard deviations of biochemical parameters analyzed are; glucose (4.8 +/- 2.8 mg/dL), calcium (38.07 +/- 5.67 mg/dL), magnesium (4.305 +/- 1.479 mg/dL), potassium (4.795 +/- 1.057 mequiv/L), sodium (190.3 +/- 15.1 mequiv/L), total protein (2.578 +/- 1.005 g/dL). These results provide necessary reference hemolymph intervals for future studies of A. leptodactylus to be used as model organism, and ecotoxicological indicator species. (C) 2012 Elsevier Ltd. All rights reserved.