The human T-cell lymphotropic virus type 1 (HTLV-I) causes a neurological disease known as HTLV-I-associated myelopathy/tropicalspastic paraparesis (HAM/TSP) in a minority of infected individuals. Although other neurological outcomes have been described theirprevalence is presently unknown. To evaluate the frequency and characteristics of neurological involvement in a population of HTLV-I-infected blood donors we investigated 196 HTLV-I positive and 196 negative blood donors from a blood center of Rio de Janeiro, Brazil.Individuals with abnormalities at the neurological examination were examined by three neurologists, and when pertinent, additionalneurological investigations were performed. Descriptive analysis, Student’st-test andv2test were employed for statistical analysis.Neurological abnormalities were found in 71 (36.2%) of the HTLV-I positive blood donors and in only 29 (14.8%) of the HTLV-I negativedonors (OR = 2.54, 95% CI = 1.67–3.59,p=0.000002). Cases of myelopathy, motor neuron disease and myopathy were only found in theHTLV-I positive group. In addition, peripheral neuropathy (PN) was significantly more frequent in the positive group (p= 0.015). Insummary, our data suggest that HTLV-I-infected individuals exhibit a wide variety of neurological manifestations apart from the classicalpicture of HAM/TSP.