1.A study was made of the catalytic transformations of the isomeric picolines and 2,6-lutidine in presence of steam over a nickel-alumina catalyst.2.Methylpyridines undergo demethylation to pyridine and complex reactions, including charcoal formation, in which the ring is broken down completely.3.The degree of total conversion and the selectivity of demethylation into pyridine at temperatures of up to 400° change in the following order for the substances studied: 4-picoline>2,6-lutidine>2-picoline>3-picoline.4.A characteristic feature for 2-picoline and 2,6-lutidine is the dehydrocondensation of intact rings on the catalyst surface with the reversible poisoning of the latter.5.4-Picoline, unlike the other methyipyridines, which are transformed by reaction with water or secondary hydrogenolysis, undergoes catalytic cracking under the conditions studied.6.It is considered that under the conditions of heterogeneous catalysis 4-picoline may be converted into the tautomeric imine form, the transformation of which (deamination) leads to the irreversible poisoning of the catalyst by the polymer that forms on its surface