Objective: Mesenchymal stem cells (MSCs) have great potential of differentiation to various lineages, regenerate injured tissues and modulate immune responses which make them useful in clinic. The reports show that the main source for isolating these cells is bone marrow, but also they can be derived from other tissues in the body. Comparative analysis between the procedures to obtain MSCs from usual sources is useful for future use. In this study, reliability, availability and total cost of Mesenchymal stem cells extraction from human bone marrow, adipose tissue and dental pulp were compared. Materials and Methods: MSCs were isolated from bone marrow by ficoll gradient and from adipose tissue and dental pulp based on extracellular matrix digestion. Isolation of MSCs was compared in the availability of each source, the tissue donation and difficulty of processing methods to isolate MSCs. The other comparing factor was reliability of each source for MSCs isolation, which the methods were compared according to; accessibility, friendly use, and efficiency (number of derived MSCs versus samples volume). At last the total cost of earning specific numbers of MSCs from each source was in mind. Statistical analysis was achieved by ANOVA test. Results: All derived cells have related characteristics of defining MSCs. Harvesting adipose tissue from human was simpler and less invasive than harvesting bone marrow and dental pulp. Method of isolating MSCs from adipose tissue was reliable and simpler than others, the reagents and equipments was less and numbers of isolated cells and expansion time was better. Total cost to derive specific numbers of MSCs was less with using adipose tissue. Conclusion: In this study we show that fat tissue is more available and reliable source for isolating MSCs in comparison with bone marrow and dental pulp.Because of easier donation and processing, and less cost of MSCs isolation. So adipose tissue can be a promising source for isolating and further use of MSCs. These findings are important because the better source for isolating MSCs for future use was defined from usual sources. In case of finding reliability in using fat tissue for MSCs isolation, it’s recommended to establish further studies for defining more characteristics of these cells for future use in lab experiments and clinic.