Blood samples were taken, in monthly intervals, for 12 months from Bohemian Spotted cows between 20 and 100 days post partum for total lipids, cholesterol, glucose and urea determination. In all, 208 cows were sampled to define the relation between reproductive performance and concentration of biochemical plasma indicators. Reproductive performance was characterized by the length of the interval (average 79.67 days), service period (average 113.64 days) and insemination index (average 1.67). Average values for the entire studied period were 5.33 mmol · l^-1 for plasma urea, 3.16 g · l^-1 for total lipids, 3.93 mmol · l^-1 for cholesterol and 3.93 mmol · l^-1 for glucose. During the investigations the length of the interval decreased from 111.39 days to 73.57 days and service period from 137.06 days to 84.61 days. The average concentrations of urea and total lipids changed in the individual months depending on changes in feed rations. Calculated correlations between the respective biochemical blood indicators and studied reproductive indicators changed in the same way. Indicators of reproductive performance were affected by the internal environment, particularly in the case of low lipaemia, and, in contrast, in the case of high blood plasma uremia.