Convolution type Calderón-Zygmund singular integral operators with rough kernels p.v.Ω(x)/|x|n are studied. A condition on Ω implying that the corresponding singular integrals and maximal singular integrals map Lp → Lp for 1 < p < ∞ is obtained. This condition is shown to be different from the condition Ω ∈ H1(Sn-1).
