Tuberculosis is an infection bacterial disease caused by Mycobactrium tuberculosis, which most commonly affects the lung, it can be treated with Anti-TB drug which are classified into first and second line drug classes where the treatment regimen consists of two phases: the initial phase and the continuation phase. Isoniazid is one of the most important first line drugs for the treatment of tuberculosis and several methods have been reported to describe the quantitative determination of isoniazid, include the derivatization of isoniazid with several aldehydes to form the corresponding Schiff's base. The aim of this study is to find a new spectrophotometric method for isoniazid (INH) analysis that combined the previously mentioned derivatization (hydrazone formation) with microwaves synthesis in order to achieve more accurate, rapid and simple method. The use of the microwaves to accelerate and quantitatively complete the reaction between isoniazid and the aldehyde is the most important modification we suggest in comparison to other previously mentioned method. Seven isoniazid Schiff's bases of several aldehydes subjected to our investigation were synthesized, purified and the maximum absorbance for each pure Schiff's base derivative was determined. The results obtained in the current study indicate that only 4- dimethylaminobenzaldehyde show no interference with its corresponding Schiff's base derivative (SIP) and enable us to quantitatively determine the concentration of SIP in the presence of the starting aldehyde. The calibration curve was made and validated. The absorbance of the sample tested was 0.54 at 421 nm, and according to the equation obtained from the calibration curve, the sample concentration result equal 3.02 mg/ml. with the percent purity 96.5 % w/w.