Hodgkin's disease (HD) is a curable disease. However, there are still many questions that remain unanswered in this illness, such as the appearance of unsuspected microscopic active illness a long time after the conclusion of treatment, We do not know of any recent publications that have microscopically studied the presence of unsuspected HD activity in patients who died from causes other than tumoral progression. This aspect was analysed in our series of patients with HD. We studied 486 patients with a median follow-up of 8 years. Autopsy was performed in 40 of 144 non-surviving patients. Active HD was found in 60% (24/40) of the patients at autopsy. Of these, 10 patients (25%, 10/40) with active HD died from causes other than tumoral progression. Six patients had minimal clinically unsuspected isolated tumor foci. In spite of technical advances and the introduction of modern and more aggressive chemotherapy, the discovery of minimal unsuspected residual HD continues in an considerable percentage of patients who die from causes other than tumoral progression.