The growth and development of groundnut (Arachis hypogaea L.) are under the influence of complex environmental factors. Understanding of the growth responses of the groundnut to environmental factors may improve the application of better management practices and develop better cultivars to overcome the problems causing reductions in yield. A two-year field experiment was conducted to determine the growth and development response of groundnut genotypes to environmental factors in the eastern Mediterranean region of Turkey in 2001 and 2002. Time from sowing to physiological maturity (R8) ranged from 2513 degrees Cd to 2588 degrees Cd in 2001 and from 2514 degrees Cd to 2573 degrees Cd in 2002 while total calendar days varied between 147 and 153 and between 156 and 161 depending on genotypes in 2001 and 2002, respectively. Dry matter accumulation in each part of the plants continued until maturity although accumulation rate differed depending on plant age. Combination of suitable temperature and photoperiod during the reproductive stages resulted in continuous and abundant reproductive plant parts, which led to delayed harvest and increased unmarketable pods. The slower growth rate due to the cooler conditions during early stages caused slower biomass accumulation in successive stages indicating the importance of initial crop growth for final yield. Therefore, the genotypes having high initial growth rate, less reproductive organs, and shorter growing period should be developed for the Mediterranean conditions by breeders. The management studies should also deal with increased initial growth rate and reduced number of flowers, pegs or pods per plant. Based on our results, groundnut has a great yield potential under the Mediterranean conditions. However, further breeding and management studies are needed to improve the yield and profitability and reduce the complications arisen from the Mediterranean climate.