1H-nuclear magnetic resonance studies, in vitro, an normal intarvertebral discs dissected from adult bovine (3-or 4-year-old) coccygeal vertebrae ware performed to clarify topographic differences in relation times [T1, T2] and relationships between the relaxation times and water content. Immediately after death, intervertebral discs were dissected from 1st/2nd and 2nd/3rd coccygeal vertebrae and divided into three specimens: the nucleus pulposus. inner anulus tibrosus, and outer anulus fibrosus. T1, T1, end water content were measured for the specimens collected from 15 intervertebral discs (untreated group). Secondly, specimens were similarly collected from 12 intervertebral discs and were treated to changed water contents (dehydrated group and hydrated groups For each treated specimen, T1, T2 and water content were measured. The specimen, showed highly significant differences (P < 0.01) in T1 values among the nucleus pulposus, inner anulus fibrosus, and outer anulus fibrosus, and also in T2 values between the nucleus pulposue and anulue fibrosus. In each of the nucleus pulposus and anulus fibrasus, a positive linear relationship (r = 0.97, P < 0.01) was found between T1 and water content. The respective regression lines for the nucleus pulposus and enulus fibrosus had different slopes, and the slope of the nucleus pulposus was significantly greater than that of the anulus fibrosus. Thus, the decrease in water content shortens the T1 fn intervertebral discs, and changes in water content have a greater influence on T1 in the rucleus pulposus than in the anulus fibrosus. Concerning the relationship between T2 and water content, the shortening of T2, according to the decrease m water content, was found at approximately 75% or more of water content in each of the nucleus pulposus and anulua fibrosus. No marked changes In T2 were found balow 75% of water content. In conclusion, T1 and T2 vary within the nucleus pulposus. Inner anulua fibrosus. and outer anulus flbrosus, and have characteristic relationships with water content in normal intervortebral discs.