The ability of wastewater stabilization ponds in treating organic materials depends on the fluctuation trend of soluble or suspended organic matter in each unit of a system to discover the material biodegradability. Therefore, this study aimed to evaluate the fluctuation trends of some ratios, including Total BOD/Total COD, Soluble BOD/Total BOD, and Soluble COD/Total COD1 in a wastewater stabilization pond. In this descriptive-analytical study, 64 samples were taken from raw wastewater and effluent entering to stabilization ponds in both warm and cold months. All measurements were performed according to water and wastewater standard test methods. Results showed a subsided trend in TBOD/TCOD ratio from raw wastewater to the secondary facultative pond effluent in both warm and cold months. The SBOD/TBOD ratio tended to hold declined trends except in the primary facultative pond effluent. Similarly, the SCOD/TCOD ratio went to possess decreased trends except in the anaerobic pond effluent. The differences in the trends of ratios and in the levels and types of contaminant removal could be due to distinctive physical, biological and chemical processes dominated in each pond. The rate and severity of the impact of each of these processes were different in each pond.