This study was conducted at the experimental area of Department of Field Crops, Faculty of Agriculture, Cukurova University in 2013 and 2014. The objective of this study was to determine the influence of planting pattern and plant population on seed yield and yield components of soybean at late double-cropped (after 15th of July) planting in Cukurova region, Turkey. The experimental design was a Randomized Complete Block Design with three replications. The Atakisi (maturity group III) variety was used as a plant material in this research. The planting pattern was used as twin-row and conventional single-row. The row spacing was 70 x 25 x 70 cm, 75 x 25 x 75 cm and 80 x 25 x 80 cm for twin-row and 70 cm for single-row pattern. Intra-row spacing of 3, 4, 5 and 6 cm was arranged for different plants population. In this research, the plant populations varied between 31.6 and 69.9 plants m(-2). According to a two-year average, the highest seed yield (4906 kg ha(-1)) was obtained from 80 x 25 x 80 x 3 cm (63.2 plants m(-1)) twin-row planting pattern while the yield was 3940 kg ha-1 in single-row planting pattern as 70 x 4 cm (35.7 plants m(-1)). The yield increase was 24.5% more than conventional single-row planting pattern (standard).