This thesis documents the experimental results of a research program investigating the effect of non-axisymmetric endwall contouring on the secondary flows and loss generation in a highly-loaded compressor cascade. The results are compared with the losses for the baseline flat endwall in order to evaluate the potential benefits.The research showed that the application of non-axisymmetric endwall contouring at design incidence modified the secondary flows near the endwall, mitigating the corner stall. The benefits from contouring were observed in terms of reductions in the secondary losses and in the underturning of the secondary flows compared to the flat endwall test case. However, these benefits were not observed at the off-design incidence studied. The application of endwall contouring generated higher secondary kinetic energy near the endwall, which penetrated deeper along the span and occupied a larger area, resulting in higher secondary and total losses as it dissipated moving downstream of the cascade.