The effect of seeding rate and stand completeness on the lucerne forage yield was studied under field conditions in the maize-growing region on loamy degraded chernozem of a weak soil reaction in the years 1987 to 1991. An experimental site with 170 m elevation had long-term average of annual temperature 9.21-degrees-C and 625 mm of precipitation, in the vegetation period 15.73-degrees-C and 352 mm. The lucerne Palava variety was sown during three successive years in the spring without a cover crop and seeding rates of 3 - 6 and 12 million germinable seeds.ha-1 in the rows of 125 mm spacing. After the emergence of the stand at the level of each seeding rate the row spacing were dug so as to obtain 100 - 80 - 60 and 40% level of stand completeness. Row spacings were uniform on the whole plot. 12 variants in total were 2 randomized in four replications in the trial. The area of the plot was 1.5 x 7 m = 10.5 m2. The yields obtained were evaluated by the analysis of variance. Besides the first cuts the effect of stand height, dry matter content, completeness and the seeding rate, as well, on the forage yield were assessed by the path analysis according to seeding rates and final levels of completeness. 20% reduction in the stand completeness on average over sowing years was associated with the yield decrease. After the seeding rate of 3 mil.ha-1, the lowest yield was achieved, though the increase of 12 mil.ha-1 did not result in the yield increase. In the second years of vegetation the decrease in the yield started at the level of 60% completeness, the seeding rate had no effect. In the third years, the decrease in the yield started even at 40% completeness; regarding the seeding rates, there was a significant difference only between the highest and the lowest seeding rates. In the evaluation for the whole duration of the trial, the lowest seeding rate reduced the yield at the level of 40% completeness. Mean yields of the stands with the seeding rate of 3 mil.ha-1 had the lower yields not later than at 60% completeness, while in the stands with seeding rates of 6 and 12 mil.ha-1 the decrease in the yield began at 40% completeness. Stands with 6 and 12 mil.ha-1 seeding rates had the equal yields at 40% completeness as the stand with the seeding rate of 3 mil.ha-1 at 80% completeness. Stand height in the first cut and the third vegetation year had a tendency to decline with a growing seeding rate (Tab. II). The yields of stands with the seeding rate of 3 mil.ha-1 had greater variability than those with other seeding rates. Path analyses conducted with the effect of completeness, seeding rate, height and dry matter content in the stand of the first cuts (Tab. III) indicate the significant effect of completeness in the first and third vegetation year, The effect of the seeding rate was insignificant, the stand height was in correlation with the yield positively, dry matter content negatively in the first year, and positively in the second one. From the path analyses according to the seeding rates (Tab. IV) it follows that on average of the lowest seeding rate the stand completeness and the stand height affected the yield only in the second vegetation year, positively in both cases. On average of the medium seeding rate, the effect of factors analyzed was insignificant and on average of the highest seeding rate the stand completeness only was in positive correlation with the yield in a sowing year. It is remarkable that at the level of seeding rate of 3 mil.ha-1 the total contribution of the factors under study to the yield formation was always the least significant. At the level of means of seeding rates of 6 and 12 mil.ha-1 this contribution was significant only in the sowing year. On average of the second years at the level of all seeding rates (and in fact in all path analyses), there was a positive correlation between the stand height and dry matter content. On average of the highest seeding rate in the third year, the value of this relation was negative. An analysis of the effect of seeding rate, stand height and dry matter according to the final levels of the stand completeness (Tab. V), maybe also as a result of low number of cases, indicate, except for the above mentioned relation between the stand height and dry matter content in the second years, there was a considerable direct effect of the stand height on the yield and highly significant contribution of the analyzed factors to die yield formation of complete stand in the second year too. The effect of the dry matter content, close below the level of significance in the third year of a complete year was worth to be noticed.