Introduction: We assessed the impact on metal levels of seafood, mollusk and fish consumption (SMFc) before urine and toenail sample donation among workers exposed to metals. Methods: This is a cross-sectional epidemiological study with 101 workers from the chemical and metal industry and 40 unexposed workers from the services sector. We measured urinary (As, Ba, Be, Cd, Co, Cu, Hg, Li, Mo, Pb, Se, Sr, Tl, V, W and Zn) and toenail (same plus Al, Cr, Fe, Mn, Ni and U) metal levels. Results: Urinary arsenic levels were higher among workers eating seafood or mollusks (102 ppm vs. 55.4 ppm; p = 0.042) or fish (109 ppm vs. 48 ppm; p = 0.007) 8 h before sample donation. Urinary mercury was associated with consumption of blue fish (11.865 ppm) and canned sardines (19.125 ppm) (p = 0.028). With respect to toenails, fish consumption was associated with aluminum (17 ppm vs. 8.6 ppm; p = 0.012) and beryllium (5 ppb vs. 1 ppb; p = 0.017). Arsenic urinary levels were associated with numbers of hours prior to sample collection since latest SMFc (p = 0.001). Conclusion: Among workers exposed to metals, seafood, mollusk and fish consumption is an important determinant of urinary arsenic levels, as sea fish for urinary mercury, but not for other metals.