The archetype chiral system MnSi belongs to the family of non-centrosymmetric cubic helimagnets where a helimagnetic ordering exists below the critical temperature of 29 K. This helimagnetic ordering is preceeded by a precursor region where SANS shows isotropic diffuse scattering. Under field, Skyrmion lattices, which are an exotic magnetic ordering is stabilized in a region just below the critical temperature. Neutron diffraction studies have shown that the helical order is suppressed for pressures exceeding a critical pressure of 14 kbar. For higher pressures, a non-fermi liquid phase is observed in which the scattering is diffuse and maximum at the [110] crystallographic directions. We propose to study MnSi with SANS under pressure to monitor the evolution of both the helimagnetic order and the precursor phenomena. in addition, we wish to study the phase diagram under magnetic fields.