In this study, effect of slope on reproduction morphology (called also as seedling in this study) in natural regenerations of Brutian pine (Pinus brutia) to contribute natural regeneration and other forestry practices was examined based on seedling height and root-collar diameter by data collected from four years old natural seedlings sampled over slope ranges (S) at end of growth period of 2020. Averages of seedling height were 97.7 cm for upper (S>40%), 96.7 cm for middle (30%<S<40%) and 106.3 cm for low (S<30%) slopes, while averages of root-collar diameter were 24.0 mm, 23.8 mm, and 24.6 mm, respectively. The results showed that lowest slope had higher growth performance than others. There were large differences within slope, and among slopes (p<0.05) according to results of analysis of variance for the characteristics. Relations between seedling height and root-collar (r=0.67, 0.70, and 0.76) were positive (p<0.05) in each slope and polled slopes (r=0.81). All seedlings of low slope were in first seedling quality class of Turkish Standard Institute, while it was 93.6% for upper slope and 96.6% for middle slope.