A common fixed point theorem in sequentially complete Hausdorff quasi-uniformizable spaces is proved. Using the additional condition for the quasi-metric $d_{\lambda}$ the condition (2) of Theorem 3.92 in the paper [4] is improved. Since Menger space $(\cal S,\cal F,T)$, where $\sup T(a,a)=1$ is a quasi-uniformizable space a corollaries on common $a<1$ fixed points in Menger spaces is obtained.