Sixteen 3-aryl-5-(4-fluorophenyl)-N-substituted-4,5-dihydro-1H-pyrazole-1-carbothioamide derivatives were synthesized and their structure were identified by UV, IR, 1H NMR, mass spectra, and microanalyses. The compounds were evaluated in vitro for their human monoamine oxidase (hMAO) inhibitory activities and their MAO-A and -B selectivity. All the compounds were found to potently inhibit MAO-A isoforms. 5-(4-Fluorophenyl)-3-(4-methoxyphenyl)-N-methyl-4,5-dihydro-1H-pyrazole-1-carbothioamide (1.0?x?10-3?mu M) was found to inhibit hMAO-A most selectively and potently. The binding mode of 5-(4-fluorophenyl)-3-(4-methoxyphenyl)-N-methyl-4,5-dihydro-1H-pyrazole-1-carbothioamide to hMAO-A was also predicted using docking studies.