Watermelon is an important vegetable crop in terms of production amount and commercial value in Turkey. Watermelons are grouped according to fruit size as icebox, mini, medium, large and very large. In this study we measured 10 seeds with 4 replications of 13 mini watermelon lines according to following characters: seed weight, seed diameter, seed length and seed thickness. We also measured fruit weight, fruit length and fruit diameter of these lines. According to the research results; it was determined that each of these parameters was statistically significant at a significance level of 1%. Line 19 and 10 had the heaviest (0.051 g seed(-1)) and lightest (0.0033 g seed(-1)) seed weight, respectively. The highest seed width, length and thickness were measured in line 19 while line 10, 14, 15 and 29 had the shortest seed diameter; while line 10 had the smallest seed size and thickness. In case of fruit weight except line 4 all 13 mini watermelon lines used in this study were in the same statistical group. Line 4 had 160 g of fruit weight, while other fruit lines ranged from 966.67 to 1540 g. Fruit diameter values of the lines showed similar results with fruit weight; 12 lines in the same statistical group with values between 11.77-13.75 cm, while line 4 came in last with 6.80 cm value. Correlation analysis showed that fruit weight is highly correlated with fruit length and width. A significant correlation was also obtained between fruit length and fruit width. In case of seed characteristics only seed length was positively correlated with seed width.