Abstract The ferromagnetic metallic oxide, SrRuO 3 ( T C ∼ 165 K) undergoes structural, magnetic and metal–insulator transitions upon substitution of Cu at the Ru-site. For x = 0.2 in SrRu 1− x Cu x O 3, the structure becomes a tetragonal with the space group I4/ mcm and there is a signature of both ferromagnetic ( T C = 65 K) and antiferromagnetic ( T N = 32 K) ordering due to possible magnetic phase separation. The antiferromagnetism arises due to short range ordering of Cu- and Ru-moments. Jahn–Teller distortion of (Ru,Cu)–O 6 octahedra indicates that the copper ions are in 2+ oxidation state with t 2 g 6 e g 3 electronic configuration. For x ≥ 0.1, narrowing of Ru-4d bandwidth by the substitution of Cu ions results in semiconducting behavior. For x = 0.3, the ac and dc susceptibility measurements indicate a spin glass behavior. The origin of spin glass behavior has been attributed to competing ferromagnetic and antiferromagnetic interactions.