A Multiple Input Multiple Output (MIMO) Microstrip Antenna (MSA) with high isolation using polarisation diversity is proposed in this paper. The structure consists of a 1×2, coaxial probe fed Rectangular MSA. The patches are kept orthogonal to reduce mutual coupling and increase isolation between antennas. The MIMO antenna structure is simulated on a low cost, easily available FR4 substrate and is fed through a 50 Ω coaxial probe. Isolation of more than 17 dB and 46 dB is obtained over 2.4- 2.48 GHz in E plane and H plane configuration respectively with edge to edge spacing of 0.032 λ0 between the antennas. The proposed MIMO antenna in orthogonal polarization configuration provides 3.2 dBi gain. This paper proposes a low cost, compact and efficient MIMO antenna design using a 1.59 mm thick FR4 substrate which provides VSWR < 2 over 2.4 - 2.46 GHz, ISM frequency band.