In this work the effects of large- and short-term debts on efficiency are tested on a set of agricultural firms. Accounting data of crop, livestock, mixed and service firms are used. First, the efficiencies of the farms are obtained by using nonparametric methods (input-oriented DEA). Then, in a second stage, censored regressions are run with different kinds of explicative variables, including financial ratios. The results show a significative and positive relationship between short-term indebtedness and efficiency, which would be agree with some theories positing that firms with higher short-run obligations make additional efforts to satisfy their payments, and this leads to an improvement of efficiency.