The Eaton-Lambert syndrome is a presynaptic neuromuscular blockade with well-defined electrical characteristics. It contrasts with the postsynaptic neuromuscular blockade which typifies myasthenia gravis. A review of the literature shows that cases do not always perfectly fit the description by Eaton and Lambert and that both kinds of blockade may be associated as in the observation reported here. Since its first description in 1956, there have been many publications on the Eaton-Lambert syndrome. However, there are cases in which both types of blockade; i.e. myasthenic and pseudo-myasthenic, are associated and the following case-report has seemed to us worthy of interest.