The objective of the study is to investigate the effects of ascorbic acid on the quality of cold-smoked trout (Oncorhynchus inykiss), with or without sodium nitrite (NaNO2). For this purpose, fish. samples (similar to 250 g) were treated with six forms of brine prepared with 10% salt which is the control, treated with 10% salt and 0.4%NaNO2, 10% salt and 0.2%NaNO2, only 2.5% ascorbic acid (Dry Salt Basis) and their combinations, and stored at +4 degrees C. The groups were analyzed after 4 days interval for microbiologic quality, biochemical quality and sensory quality. According to the results, the samples treated with only ascorbic acid increased the shelf-life of smoked fish about > 8 days. TVB-N value of the control group was average 41.72 mg/100 g after 16 day; the group containing ascorbic acid was on average 30.53 mg/100 at this time. Ascorbic acid reduced the residual nitrite in all groups. The residual nitrite disappeared in the ascorbic acid including groups after 20 day.