Morphology of hypereutectoid cementite is essential for mechanical properties of ultra-high carbon steels. The influence of cooling rate of hypereutectoid steel on morphology of -hypereutectoid cementite is studied. Using results of dilatometric experiment the diagram "time – temperature – transformation" (TTT-diagram) was plotted for hypereutectoid ultra-high carbon steel containing 1.56%C. Cooling of samples with rates of 0.1 to 30 ºC/s from 1150 ºC was carried out in quenching dilatometer Linseis L78 R.I.T.A. The critical points of steel are: M s = 138 °C; A C1 = 742 °C; A Cm= 960 °C. Metallographic studies of cooled dilatometric samples showed that an increase in the rate of cooling leads to changes of cementite morphology. Widmanstatten cementite precipitates at cooling rates faster than 1 ÷ 3 ºC/s while net-shape cementite is typical for slow cooling. Accelerated cooling does not completely prevent the formation of cementite network at the grain boundaries. Morphology of hypereutectoid cementite is in dependence on the grain size of austenite. Increasing of the austenite grain size produces needle of widmanstatten cementite at lower cooling rates.