Lead-free sodium niobate (NaNbO3, NN) and potassium niobate (KNbO3, KN) nanopowders were successfully synthesized by a simple and green synthesis processin gelatin media. Gelatin, which is a biopolymer, was used as stabilizer. In orderto determine the lowest calcination temperature needed to obtain pure NN and KN nanopowders, the produced gels were analyzed by thermometric analyzer (TGA).The produced gels were calcined at 500C and 600C. The structural and optical prop-erties of the prepared powders were examined using X-ray diraction (XRD) technique,transmission electron microscopy (TEM), and UV{Vis spectroscopy. The XRD results revealed that pure phase NN and KN nanopowders were formed at low temperature calcination of 500C and 600C, respectively. The Scherrer formula and size-strain plot (SSP) method were employed to estimate crystallite size and lattice strain of the samples.The TEM images show that the NN and KN samples calcined at 600C have cubic shape with an average particle size of 60.95 and 39.29 nm, respectively. The optical bandgap energy of the samples was calculated using UV{Vis diused reectance spectra of the samples and Kubelka {Munck relation.

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