Silver nanoparticles were synthesized using the fruit extracts of Momordica charantia (Mc-AgNPs). The structural characterization of Mc-AgNPs was performed by UV–vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). UV–vis recorded the absorbance spectra at 460 nm. XRD shows the crystalline nature of silver nanoparticles with various Bragg's reflection peaks at 111, 200, 220 and 311. FTIR spectra of the synthesized Mc-AgNPs showed strong bands at 1382, 1203, 1151, 1102, 1013 and 654 cm−1 which corresponds to O–H, C–H, C–C, C–OH and C–N groups. TEM showed the spherical shape of Mc-AgNPs with particle size between 16 nm. The antibacterial activity of Mc-AgNPs was tested against Gram-positive and Gram-negative bacteria. Mc-AgNPs showed greater inhibition of Enterococcus faecalis at 100 µg ml−1 compared to Aeromonas hydrophila. The biofilm inhibition of Mc-AgNPs was also higher against E. faecalis compared to A. hydrophila. © 2016 Elsevier Ltd