ABSTRACT The aim of this study is to analyze the source from which SMEs obtain resources for their operation, we analyze the literary theories that talk about how SMEs apply for a credit and the various obstacles they face during the process. The reviewed academic literature shows that firms sometimes prefer to keep operating on their own resources or seek an external source via debt, thus, new capita input becomes last, as this can contribute to company control loss. In addition, the literature reveals a number of obstacles that the company has when it wants to apply for a credit, such as: size, the small ones have less possibilities; the age, the younger companies do not have a credit history which is required by most financial institutions; the opacity, SMEs do not usually have adequate control of their information and do not generate the minimum information required in the processing of crédito approval; guarantee, on many occasions in order to dilute the risk in the credit transaction a collateral is deposited, though SMEs not always have or are available for that purpose and last, interest rate, the highest cost of credit is the interest payment, cost can be quite high for a SME. A model is provided from these theories which frames variables that can help or limit credit approval from companies. This is done to establish which variables are the main ones and how they influence crédito approval. Also, if some of these variables can help or facilitate the provision thereof, for example, the lending relationship, defined as the information the bank has of the company through the contact and business relation with the company. The results were analyzed out of 208 national surveys, the empirical study analyzed through the structural equation technique which it will help us compare the assumptions made and to validate the model proposed in this study. The empirical results show that the causal relation among information, guarantee, lending relationship and age of the company, with obtaining a credit is confirmed, and does influence the outcome. We also found a relation between the cost of interest which is influenced by information, the size of the company and the guarantee. Regarding the interest rate, the dependence respect to obtaining a credit is not a significant influence, thus, this hypothesis is discarded. This study contributes to a better understanding among the obstacles of SMEs to obtain a credit and the relation between them to ease the strain. It also shows a more detailed role of the cost of interest among the different variables that arise from the previously established models.