Chalcones has been known to have many biological activities, for example as an antitumour. These research synthesized and observed the cytotoxicity effects against HeLa cells of the 3,4- dichlorochalcone analog compound. These compounds were synthesized by modifying in the aromatic ring which attached at β position to the keton carbonyl. The aromatic ring was furanylaromatic. Synthesis of 3,4-dichlorochalcone analog compound was carried out by Vogel method using starting materials of furanylbenzaldehide and 3,4-dichloroacetophenone. These purity test of synthesized compound was analyzed using thin layer chromatography, melting range, and GC methods. Structure elucidation was determined by using physical methods, such as UV spectrophotometer, IR spectrophotometer, H1-NMR spectrometer, and MS spectrometer analysis. The compound was then observed the cytotoxicity effects against HeLa cells by MTT method. The result indicated that the 3,4-dichlorochalcone analog compound had been able to be synthesized, purified, and it had structure as a predicted compound, furanyl-3’,4’-dichlorochalchone. The cytotoxic results shown that the 3,4-dichlorochalcone analog compound with the IC50 value of 23,5 μg/ml.Kalkon telah dibuktikan mempunyai bermacam-macam aktivitas biologis, salah satu di antaranya sebagai antitumor. Penelitian ini bertujuan mensintesis senyawa analog 3,4- diklorokalkon dan meneliti efek sitotoksiknya terhadap sel HeLa. Senyawa tersebut disintesis dengan memodifikasi cincin aromatik yang diserang pada posisi β pada karbonil keton. Cincin aromatiknya berupa furanil aromatik. Sintesis senyawa analog 3,4 diklorokalkon menggunakan metode Vogel menggunakan material awal furanilbenzaldehida dan 3,4-dikloroasetofenon. Kemurnian hasil sintesis dianalisis dengan kromatografi lapis tipis, jerak lebur, dan kromatografi gas. Elusidasi struktur ditentukan dengan analisis spektrofotometer UV, spektrofotometer IR, spektrometer H1-NMR, dan spektrometer massa. Senyawa lalau diamati efek sitotoksiknya terhadap sel HeLa dengan metode MTT, Hasil penelitian menunjukkan bahwa senyawa analog 3,4 diklorokalkon telah disintesis, murni, dan strukturnya adalah furanil-3’,4’-diklorokalkon sesuai yang diprediksikan dengan nilai IC50 aktivitas sitotoksik terhadap sel HeLa sebesar 23,5 μg/ml
