Abstract : ​An almost Anosov flow is a flow having continuous flow-invariant splitting of the tangent bundle with exponential expansion/contraction in the unstable/stable direction, except for a finite number (in our case a single) periodic orbits. Roughly, almost Anosov flows are perturbed Anosov flows, where the perturbation is local around these periodic orbits, making them neutral. For this type of flows, we obtain limit theorems (stable, standard and non-standard CLT) for a large class of (unbounded) observables. I will present these results stressing on the method of proof. This is joint work with H. Bruin and M. Todd.