Results of planting density effects on production of nursery plants type 1/2 of three black poplar clones section Aigeiros (Duby) grown on sandy fluvisol are shown in this paper. The clone PE 19/66, B-229 (Populus deltoides Bartr. ex Marsh.), and clone Pannonia (Populus × euramericana (Dode) Guinier) were studied, while applied planting densities for production of nursery plants type 1/2 ranged from dense to scarce: 0.80×0.20 m, 0.80×0.25 m, 0.80×0.30 m, 0.80×0.40 m, 0.80×0.50 m. The results of investigation showed that there were differences in survival rate and average height of nursery plant type 1/2 between clones, while effect of planting density was manifested only on average height of nursery plants. Studied clones exhibited different height structure of nursery plants depending on planting density, which was confirmed by numerical parameters and non-parametric Kolmogorov-Smirnov test. Applied different criteria relating to minimal nursery plant height of 2.0 m, 2.5 m, 3.0 m and 3.5 m showed that in so called "low" criterion (2.0 m) the percentage of unusable nursery plants was minimum for all planting densities and in all three poplar clones, and thus the planting density should be based on the quantity of produced nursery plants per hectare. In so called "high" criterion (3.5 m) differences in number of produced nursery plants per hectare between different planting densities were diminishing, and the percentage of unusable nursery plants remained high even at the lowest planting densities, shifting the choice from high towards lower planting densities. In so called "mean" criterion relating to minimum nursery plant height (2.0 and 2.5 m), which is the most often encountered in nursery production, the optimal density (which is found within applied planting densities) can be chosen taking the quantity of nursery plants per hectare into account.