Modification of chitosan any Schiff base reaction with acetophenone derivatives was done. Fourier transformer infrared analysis (FT-IR), scanning electron microscope (SEM), and X-ray diffraction (XRD) were used as the appropriate characterize the Schiff base derivatives. Thermal behavior of the prepared materials was also studied. Various biological activities were examined for the prepared materials antimicrobial activity including antibacterial (studied against Streptococcus sp. Bacillus subtilis and Sarcina lutea as an example for gram-positive bacteria and Pseudomonas aeruginosa and Escherichia coli as an example for Gram-negative bacteria), anti-fungal (against Candida albicans) and anti-protozoal (against Trypanosoma cruzi and Leishmania donovaniwas). Antioxidant activity of chitosan and its Schiff base derivatives was detected using the FRAP and DPPH techniques. Colon carcinoma (Colo 205), hepatocellular carcinoma (Hep G2), urinary bladder carcinoma (T24P) and embryonic kidney adenocarcinoma (293) used to examine the anticancer activity of chitosan and its modified derivatives. The new chitosan Schiff base derivatives showed superior anti-bacterial, antifungal, anti-protozoal and antioxidant activity than parent chitosan. But in case of anticancer test of HebG2 and T24P chitosan was more effective than the modified derivatives.