To further describe the clinical and epidemiological characteristics of Penicillium marneffei infection in human immunodeficiency virus (HIV) infected patients in India. In continuation of our earlier report of four autochthonous cases of P. marneffei infection in HIV infected patients from Manipur, a northeastern state of India, we studied additional 46 cases of penicilliosis marneffei from the same area over a period of 19 months (April 1998-October 1999). Clinical, microbiological features, and therapeutic responses were analyzed in 36 of the 46 patients as ten patients were lost to follow-up. Of the 198 HIV positive patients attending the J. N. Medical Hospital, Imphal, Manipur state during the period mentioned, 46 (25%) had P. marneffei disseminated infection. Of the 36 patients analyzed 31 (86%) were intravenous drug abusers, 1 had multiple sex partners, and 3 females acquired HIV infection from their respective spouses. A 9-year-old child acquired HIV infection by vertical transmission. The common clinical symptoms included fever (97%), weight loss (100%), weakness (86%), anemia (86%), and characteristic skin lesions (81%). Presumptive diagnosis was made by microscopic examination of Wright's-stained smears of fine needle aspirated material from skin lesions and lymph nodes showing numerous intracellular and extracellular, oval, elongated, yeast-like cells dividing by fission. The etiologic agent P. marneffei was isolated in culture from clinical materials in 10 cases when isolation was attempted. All patients were treated with oral itraconazole. All, except one patient, responded favorably to treatment within 7 days. Thus, the present cases further confirm the endemicity of penicilliosis marneffei in Manipur and resemble the epidemiology and clinical course of patients from other parts of south-east Asia.