While studying a group of children with the visceral larva migrans syndrome we encountered in the patient group a child with agammaglobulinemia. This child, in spite of an almost complete absence of immune globulins, exhibited the massive eosinophilia characteristic of the tissue phase of helminth infections. Case Report L.C.S., a 16-month-old Puerto Rican boy, was admitted to the University Hospital in San Juan on February 19, 1963, because of fever, wheezing and cough of 3 weeks' duration. His past history revealed chronic diarrhea and episodes of purulent conjunctivitis, otitis, and pneumonia. Pica had been noted for 5 months, and dogs, cats, pigs, and cows were present near the child's play area.