It is intended to develop a fat substituted, low fat and functional fermented sausage by determining the effects of fat substitution (15, 30 and 45% ratio) with hazelnut paste in traditional fermented sucuks. The increase in fat substitution ratio increased the dry matter but decreased the fat and cholesterol content in hazelnut added sausages. Control samples cholesterol content were 89.47 ± 0.55 mg/100 g while 15, 30 and 45% hazelnut substituted samples were 87.33 ± 1.20, 84.93 ± 0.61 and 82.28 ± 0.50, respectively. Hazelnut added sucuks had lower cholesterol level and a functional fatty acid profile with a indexes of atherogenicity and thrombogenicity. However hazelnut added sucuks had increased TBARS values. The sensory properties of sucuk did not adversely affect by replacement of fat with hazelnut.