The KLOE experiment at the Frascati \phi -factory DA\Phi NE has measured the hadronic cross section \sigma (e⁺e^-\to \pi ⁺\pi ^-\gamma _ISR) using two different selection criteria for the Initial State Radiation (ISR) photon:   (i)  requiring the photon emission at small polar angle and  (ii) detecting the photon at large polar angle in the electromagnetic calorimeter. Using a theoretical radiator function we extract the non-radiative cross section \sigma (e⁺e^-\to \pi ⁺\pi ^-) and we compute the \pi ⁺\pi ^- contribution to the anomalous magnetic moment of the muon. Results presented in this paper come from the analysis of data collected in 2002 (240 pb^-1 of integrated luminosity) with an improved systematic uncertainty compared to a published KLOE analysis, which was based on 2001 data.

PACS numbers: 13.40.Em, 13.40.Gp, 13.60.Hb, 13.66.Bc