It is one of three positional isomers of methylpyridine, whose structures vary according to where the methyl group is attached around the pyridine ring.

This colorless liquid is a precursor to pyridine derivatives that have applications in the pharmaceutical and agricultural industries.

Like pyridine, 3-methylpyridine is a colorless liquid with a strong odor and is classified as a weak base.

Pyridine derivatives (including 3-methylpyridine) are environmental contaminants, generally associated with processing fossil fuels, such as oil shale or coal.

3-methyl pyridine is biodegradable, although it degrades more slowly and volatilize more readily from water samples than either 2-methyl- or 4-methyl-pyridine.,[7][8] 3-Methylpyridine is the main precursor to niacin, one of the B vitamins.