The Maramureş Mountains are situated in the North of Eastern Carpathians, at the border between Romania and Ukraine. Our researches were concerned with analyzing the bed material size and shape for Ruscova and Vaser rivers, from this mountain unit, and with the identification of the factors which influences these characteristics. Samples was taken from 5 sites for each river, using the Wolman (1954) (pebble counts) method, for surface particle sampling from gravel and cobble bed streams. Sorting and abrasion of particles has little influences in variations of median grain diameter D50 (mm) along rivers. A more important role has the amount of high resistant rocks (metamorphic and volcanic rocks) to the transport in fluvial regime, in part of hydrographic basins situated between the sample sites.