To evaluate the long term creep of resin grouted masonry an 8 month creep test has been executed on two cylinders of grouted stone masonry, bored out of the St. Mary's Basilica tower at Tongeren, Belgium. The creep of the grouted masonry has been measured and an extrapolation has been elaborated according to the relationship proposed by Bazant. Experimentally measured and mathematically predicted creep evolution fit very well. The important creep values after consolidation show the necessity of a good over-all consolidation of the masonry.