The antimicrobial activities of eleven maleimide derivatives were tested in this study. Out of the eleven samples, N-(4-fluorophenyl) maleimide, N-(4-chlorophenyl) maleimide and N-(4-bromophenyl) maleimide were synthesized by reacting maleic anhydride with 4-fluorophenylaniline, 4-chlorophenylaniline and 4-bromophenylaniline, respectively in the presence of acetic acid, by refluxing overnight. Crystals were successfully obtained after the products were recrystallized with different mixture of solvents. Their chemical structures were confirmed by infrared spectroscopy (IR), 1 H and 13 C Nuclear Magnetic Resonance (NMR) and melting point determination. Subsequently, all the samples were screened for their biological activity using disc diffusion method. The bacteria chosen for this study were Gram-negative Escherichia coli, Gram-positive Bacillus subtilis and yeast Saccharomyces cerevisae. Positive control for bacteria was streptomycin and nystatin for the yeast. M1 to M6 compounds gave remarkable result at low concentrations whereas M8, M9 and M11 compounds are mostly inactive up to a high concentration. In contrast, the unsubstituted maleimide, M7 was highly reactive towards both bacteria and yeast at low and high concentrations. Keywords: N-substituted maleimide, antimicrobial, disc diffusion AbstrakKajian antimikrob terhadap sebelas terbitan N-maleimida telah diuji dalam kajian ini. Tiga daripada sebelas sebatian maleimida yang diuji, iaitu N-(4-florofenil)maleimida, N-(4-klorofenil)maleimida dan N-(4-bromofenil)maleimida telah disintesis melalui tindakbalas maleik anhidrida dengan 4-florofenilanilina, 4-klorofenilanilina and 4-bromofenilanilina secara berasingan dalam kehadiran asid asetik, diikuti dengan refluks semalaman. Mendakan tidak berwarna telah diperolehi setelah penghabluran semula dilakukan ke atas hasil sintesis. Pencirian struktur sebatian dilakukan melalui kaedah spektroskopi Infra Merah (IR), 1 H dan 13 C Resonans Magnet Nukleus (NMR) dan penentuan takat lebur. Seterusnya, kajian antimikrob bagi kesemua sebelas sampel dilakukan melalui kaedah resapan cakera. Bakteria yang digunakan dalam kajian ini ialah Escherichia coli dan Bacillus subtilis manakala yis yang digunakan ialah Saccharomyces cerevisae. Kawalan positif untuk bakteria ialah streptomisin dan nystatin untuk yis. Sebatian M1 ke M6 mencatatkan keaktifan yang baik pada kepekatan rendah. Sebatian M8, M9 dan M11 kebanyakannya tidak menunjukkan keaktifan walaupun kepekatan dos ditingkatkan. Berbeza pula dengan sebatian M7, iaitu maleimida yang tidak mempunyai sebarang kumpulan gantian yang menunjukkan keaktifan yang tinggi terhadap kedua-dua bakteria dan yis pada kepekatan rendah dan tinggi.Kata kunci: maleimida N-gantian, antimikrob, kaedah resapan cakera