We consider a ferrofluid system consisting of magnetic particles interacting with a magnetic dipole-dipole interaction. We study the strong magnetic field regime where all magnetic dipoles are completely polarized in the direction of the magnetic field. We introduce a lattice gas model that serves to describe space ordering phenomena in such systems. It is found that, within mean field theory, this model predicts a second order phase transition to a phase with inhomogeneous lamellar-like ordering below a certain critical temperature. © 2009 Elsevier Ltd. All rights reserved.