Endemic goiter was thought to essentially spread in the southern part of Cameroun. In fact the North-East Benoué (NEB) area also appears to be concerned. We studied 1242 individuals from 5 representative villages. The overall goiter frequency was 28.4%. Study of emigrants showed a spreading of the endemic area towards the boundary part of Tchad. However increase of morbidity was related to the duration of settlement in NEB (18% after 1 year vs 34% after 5 years, p less than 0.01). Samples of urine from one single micturition were kept at 4 degrees C and assayed for iodide within 3 days. The results exhibited marked iodine deficiency (iodide : 9.6 +/- 1.5 micrograms/l; urinary ratio : iodide/creatinine : 17.9 micrograms/l). The way of preserving urine before iodine assay was critical. After 8 days of daylight exposure of the samples at 30 degrees C, the most part of assayable iodine had disappeared. The goitrogenic effect of manioc was weak : there was no relationship between the presence of goiter and the amount of ingested manioc. Concentration of thiocyanates in urine was correlated neither with manioc consumption nor with goiter volume. An automatic classification was obtained by computerization of several parameters. 88% of the patients distributed in 10 groups whose goiter frequencies were markedly different. Because of the well-defined characteristics of each group, it seems possible to perform valid biological or nutritional studies using a limited number of individuals.