Litter decomposition is the fundamental pathway for the turn of carbon, nitrogen and nutrients to terrestrial ecosystem and strongly influenced by climatic variables, litter quality and microbial activity. This study was carried out to investigate the effects of two different parent materials (conglomerate and marl) on litter decomposition and the relationships between litter quality and decomposition rate of Pinus pinea L. and Ceratonia siliqua L. in the East Mediterranean Region of Turkey. Fresh fallen litters from P. pinea and C. siliqua plants were determined contents of C, N, P, lignin and cellulose. The litter bag method was used to determine their mass loss in the sampling area for 544 days. Litter mass loss in decomposition varied in the following order: Ceratonia(marl)>Ceratonia(cong)>Pinus(cong)>Pinus(marl). There were no significant differences among the samples in terms of lignin contents of initial litter while cellulose content was only statistically significant between Pinus(cong) and Ceratonia(cong) (p<0.05). These results suggested that litter decomposition is affected from different parent materials (conglomerate and marl) and plant diversity.