The manganese(II) complex with the non-steroidal antiinflammatory drug niflumic acid has been synthesized and characterized. The crystal structure of the complex [Mn(O-niflumato)2(methanol)4] has been determined by X-ray crystallography, where a monodentate coordination of niflumato ligand was revealed. Niflumic acid and its Mn(II) complex exhibit good binding affinity to human or bovine serum albumin proteins with high binding constant values. UV study of the interaction of the compounds with calf-thymus DNA (CT DNA) has shown that the compounds can bind to CT DNA and [Mn(O-niflumato)2(methanol)4] exhibits higher binding constant to CT DNA than free niflumic acid. The compounds can bind to CT DNA via intercalation as concluded by DNA solution viscosity measurements. Competitive studies with ethidium bromide (EB) have shown that the compounds can displace the DNA-bound EB suggesting strong competition with EB.