Background/Aim: There is significant loss of microvasculature and impaired angiogenesis in rat remnant kidney (RK). Placenta growth factor (PlGF) is a potential angiogenic growth factor. In this study, we investigate the changes of microvasculature and expression of PlGF in the first 4 weeks of the early stage of a rat RK model. Method: RK was induced by right nephrectomy and ligation of two of the three branches of the left renal arteries (equivalent to 5/6 subtotal nephrectomy). Blood urea nitrogen (BUN), serum creatinine (Scr), and blood pressure (BP) were measured. Proliferation of endothelial cells was identified by double staining of two antibodies, anti-rat endothelial cell (RECA-1) and antiproliferating cell nuclear antigen (PCNA). RT-PCR and Western blot were used for PlGF analysis. Results: BUN, Scr and BP remained stable after rising within the first week. An angiogenic response occurred in RKs, with an increase in the proliferation of peritubular and glomerular endothelial cells. Both PlGF protein and mRNA expression were significantly upregulated 2- to 3-fold in RK at week 1 and week 2, compared to the sham-operated group (p < 0.05). Conclusion: The expression of PlGF is upregulated and coincident with an early angiogenic response in rat RK, suggesting that PlGF may be involved in angiogenesis in progressive renal injury.