In this paper we prove that a transitive fuzzy relation R on a set X can be extended to a total transitive fuzzy relation Q on X preserving the irreflexivity of R. This generalizes a classical theorem of Szpilrajn that asserts that any strict order on X can be extended to a total strict order on X. The extension theorem that we obtain will be used in the fuzzy analysis of a classical Richter theorem in consumer theory.