  We report the discovery of eight new extremely metal-poor galaxies (XMPGs;
12+log(O/H) < 7.65) and the recovery of four previously known or suspected
XMPGs (IZw18, HS0822+3542, HS0837+4717 and A1116+517) using Sloan Digital Sky
Survey (SDSS) spectroscopy. These new objects were identified after an analysis
of 250,000 galaxy spectra within an area of ~3000 deg^2 on the sky. Our oxygen
abundance determinations have an accuracy of $\le$ 0.1 dex and are based on the
temperature-sensitive [O {\sc iii}] $\lambda$4363 \AA line and on the direct
calculation of the electron temperature. We briefly discuss a new method of
oxygen abundance determinations using the [O {\sc ii}] $\lambda$7319,7330 \AA\
lines, which is particularly useful for SDSS emission-line spectra with
redshifts $\le$~0.024 since the [O {\sc ii}] $\lambda$3727 \AA emission line
falls outside of the SDSS wavelength range. We detect XMPGs with redshifts
ranging from 0.0005 to 0.0443 and $M_g$ luminosities from $-$12\fm4 to
$-$18\fm6. Our eight new XMPGs increase the number of known metal-deficient
galaxies by approximately one quarter. The estimated surface density of XMPGs
is 0.004 deg$^{-2}$ for $r$ $\le$ 17\fm77.
