  Using an updated SN list and galaxy parameters from the RC3 catalog, we have
revisited two well know biases affecting SN searches. We show that the bias in
the central region of galaxies is negligible for galaxies closer than 40 Mpc
(H=75), but causes the loss of almost 50% of SNe in the distance range 80-160
Mpc. This bias has a weak dependence on the galaxy and SN types. Instead the
bias due to the inclination of spiral galaxies is more severe especially for
SNII in late spirals with only 1 SNe out of 5 being detected in edge--on
galaxies. The two effects seem interconnected with a more severe loss of SNe in
the central part of inclined spirals. Our best estimates of the SN rates are
reported along with a quantitative estimates of the different source of errors.
