In adaptive filtering, it is typical to assume that the adaptive filter impulse response is of the same length as the impulse response of the unknown system to be identified. However, in practice this is usually not the case. The filter impulse response is typically shorter and hence called deficient length. The Euclidean Direction Search (EDS) algorithm is a relatively new adaptive filtering scheme, which combines the benefits of fast convergence of the RLS and the low computational complexity of the LMS algorithm. In this paper, we analyze the performance of the deficient length EDS algorithm. Computer simulation results are encouraging and agree with the theoretical findings.