This study aims to investigate the effect of phenolic compounds extracted grape seed and pomegranate seed on characteristics of strained yoghurts produced from sheep milk. Firstly, phenolic compounds were extracted grape and pomegranate seed and their amounts for strained yoghurts were determined by estimating their phenolic activities. Also antimicrobial activity of seed extracts was determined. On 1(st), 7(th), and 14(th) day of storage, chemical analyses as dry matter, protein, acidity, pH, proteolysis and peroxide value and microbiological analyses such as enumeration of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus and sensory analysis were conducted on strained yoghurt samples. According to analysis results, while addition of phenolic compounds affects chemical and microbiological properties of strained yoghurt positively, sensory quality was affected negatively.