Techniques are disclosed for forming dual-strain fins for co-integrated n-MOS and p-MOS devices. The techniques can be used to monolithically form tensile-strained fins to be used for n-MOS devices and compressive-strained fins to be used for p-MOS devices utilizing the same substrate, such that a single integrated circuit (IC) can include both of the devices. In some instances, the oppositely stressed fins may be achieved by employing a relaxed SiGe (rSiGe) layer from which the tensile and compressive-strained material can be formed. In some instances, the techniques include the formation of tensile-stressed Si and/or SiGe fins and compressive-stressed SiGe and/or Ge fins using a single relaxed SiGe layer to enable the co-integration of n-MOS and p-MOS devices, where each set of devices includes preferred materials and preferred stress/strain to enhance their respective performance. In some cases, improvements of at least 25% in drive current can be obtained.