This study was carried out to assess the changes in chemical composition and heavy metal levels of mullet fish following hot and cold smoking. Mullet fish samples were collected in September 2020 from two fish farms (1 and 2) in Fayoum Governorate, irrigated by El-Batts and El-Wadi drains, respectively. The findings of determining biochemical characteristics (moisture, protein, lipid, and ash) revealed that the moisture content decreased from initial 74.82% to 63.22 and 59.32 in raw, cold and hot smoked products obtained from farm 1, respectably. While these levels were 72.10% decreased to 61.25% and 58.06% in raw, cold and hot smoked products, while protein and lipid contents increased after smoking in both fish farms samples. Also, ash contents have been found to increase from 1.23% and 1.11% in raw samples to 5.14% and 6.52% in cold and hot smoked products from farms (1 and 2).  Levels of Lead (Pb), Cadmium (Cd) and Zinc (Zn) have been determined in raw and smoked products. Lead (Pb) levels were 0.013 ppm in raw samples from farm 1, increased from 0.103 ppm in farm 1 raw samples to 0.210 and 0.252 ppm in cold and hot smoked samples, respectively. Sam trend obtained in farm 2 samples.  Cadmium (Cd) and Zinc (Zn) levels increased after cold and hot smoking in all mullet fish samples.