Agricultural wastes have increased with the intensive production in recent years. These wastes that affect the physical, chemical and biological properties of soils should be composted and added to soil. In this study, composts were consisted of different agricultural wastes such as greenhouse wastes-GPW, used co-copeat wastes-UCW, spent mushroom composts-SMC and at different ratios. Used cocopeat wastes were especially chosen in this experiment because it was not preferred in compost mixtures up to the present. Five different compost mixtures were added to the soil and their effects on growth and nutrient contents of lettuce plants were determined. The experiment was carried out during two successive seasons (autumn and spring). The results showed that plant growth and yield were found higher in the compost applications than in control. Generally the highest values were obtained from M1 application (80% GPW + 10% UCW + 10% SMC) for many parameters.