A review of the main characteristics of low-latitude sources in the Third EGRET catalog is presented. There are 75 unidentified gamma-ray sources at |b| < 10 o. About a half of these sources are positionally correlated with potential galactic gamma-ray emitters such as supernova remnants, OB associations and early-type stars with very strong stellar winds. The other half is formed by sources without positional correlation with known galactic objects capable to generate gamma-rays significant enough as to be detected by EGRET. A variability analysis shows that this second group of sources contains a population of objects with high levels of gamma-ray variability. The variable population resembles very much the AGN population, although its surface density is much higher. The parent population of these variable sources could be a new class of high-energy galactic objects which are modest emitters at lower frequencies.