Unilateral pulmonary edema (UPE) due to cardiac causes is an unusual clinical finding and typically emerges on the right side. UPE poses a diagnostic challenge due to difficulty distinguishing infiltrative pneumonia from cardiogenic edema on chest imaging. Consequently, corrective clinical management is significantly delayed in UPE compared to bilateral cardiogenic pulmonary edema. We present a very rare case of left-sided cardiogenic pulmonary edema due to acute severe MR wherein a prompt cardiac evaluation for UPE led to successful corrective surgery and favorable outcome.