Measurements were performed at 37 degrees C on 49 fresh samples excised from cancerous (n = 16) or non-malignant (n = 33) thyroid tissues of 23 patients. They were carried out for protons at a frequency of 10.7 MHz with pulse sequences (90 degrees-t-90 degrees) and (90 degrees-t-180 degrees-t) for T1 and T2 respectively. The estimates were correlated to histopathology with quantitative measurements of the proportions of colloid, thyroid epithelium, fibrosis, and haemorrhage tissue. Discriminant analysis of malignant and non-malignant tissues using T1 and T2 values, was not successful. T1 and T2 values were correlated to each other. Both were correlated to the proportions of water, thyroid epithelium and haemorrhage and inversely correlated to the amount of colloid. Multiple regression analysis revealed that T2 values were more tissue-specific than T1 values. The analyses indicate possibilities to identify different thyroid tissues by magnetic resonance imaging, especially by T2 weighted MR images.