In the calculation of the rolling bearings lifetime are taking in to consideration the distribution of the work load on each rolling elements, obliquity, internal operation clearance and pre-stressing. In the case of a rolling bearing with a defect, the internal operation clearance have an influence upon the evolution of its deterioration and remaining lifetime by: internal manufacturing clearance; the expansion of the inner ring when the rolling bearing is mounted on a adapter sleeve; the contraction of the outer ring when the rolling bearing is mounted in the housing; and the temperature difference between rolling bearing rings during operation. This paper presents an experimental study regarding to the influence of the internal operation clearance of the ZKL 1205K rolling bearing upon the remaining lifetime in same operating conditions.