Three patients with Lambert-Eaton myasthenic syndrome (LEMS), two men aged 61 and 64 and a woman aged 55 years, all developed proximal weakness, depressed tendon reflexes and autonomic dysfunction. Although this clinical triad is highly suggestive for LEMS, the disorder had not been recognized initially. The woman had a small-cell bronchial carcinoma, treated successfully by chemotherapy, whereafter the LEMS symptoms gradually disappeared. The first man was treated with 3,4-diaminopyridine and azathioprine, whereupon his symptoms diminished. The other man had only slight complaints and refused drug treatment. The three cases illustrate that presentation and course of LEMS can vary between patients. Furthermore, clinical and electrophysiological features can suggest myasthenia gravis, myopathy or axonal polyneuropathy. Therapeutic options and the risk of underlying malignancy make early diagnosis important. In conclusion, in every patient presenting with unexplained proximal weakness, LEMS should be considered, especially if depressed tendon reflexes and autonomic dysfunction are found as well.