We study constant mean
curvature foliations with isolated center singularities in 3-dimensions. We prove that
the leaves become round upon approaching a center. We also derive a priori curvature
estimates for constant mean curvature foliations without stability condition. A
complete existence, uniqueness and non-existence result for constant mean
curvature foliations around a center is derived as a consequence. These results
are extended to constant mean curvature foliations on asymptotically flat
ends.