We report for the first time the successful synthesis of polycrystalline PrBa2Cu4O8 (Pr124) at ambient oxygen pressure. Pr124 has been prepared by nitric pyrolysis and oxalate coprecipitation methods, and both methods yield qualitatively the same results. Powder X-ray-diffraction patterns of samples prepared by both methods show a nearly single "124" phase. Thermogravimetric analysis indicates no oxygen loss until the temperature is higher than 800°C, revealing that its thermal stability is distinct from that of PrBa2Cu3O7. Electrical resistivity ρ(T) shows metallic behavior at low temperatures. These results show that the quality of the samples prepared at ambient oxygen pressure is comparable to that by hot isostatic pressing technique.