This article studies the aggregation diffusion equationwhere ∆ α 2 denotes the fractional Laplacian and K = x |x| a is an attractive kernel. This equation is a generalization of the classical Keller-Segel equation, which arises in the modeling of the motion of cells. In the diffusion dominated case a < α we prove global well-posedness for an L 1 k initial condition, and in the fair competition case a = α for an L 1 k ∩ L ln L initial condition. In the aggregation dominated case a > α, we prove global or local well posedness for an L p initial condition, depending on some smallness condition on the L p norm of the initial condition. We also prove that finite time blow-up of even solutions occurs, under some initial mass concentration criteria.