Background and Objective: Photodynamic therapy is a treatment that uses photosensitizer and intense visible light. When photosensitizers get exposed to a specific light wavelength (preferentially in the red region), they produce reactive oxygen species that are toxic to cells. Recently, attention has been focused on porphyrins and their analogs as photosensitizers. Zn (II) tetrapyridinoporphyrazin complex is a water-soluble photosensitizer that has a good potential for application in photodynamic therapy. In this study, phototoxic effect of this complex on HeLa cancer cell line has been investigated. Materials and Methods: HeLa cell cultures were treated with different concentrations of Zn (II) tetrapyridinoporphyrazin. The cytotoxic effects were measured both in the presence and absence of light using the MTT assay. The light source was a 150W tungsten halogen lamp equipped with a red filter. Results: Our data indicate that porphyrazine’s photocytotoxicity is remarkably more significant than its cytotoxycity in the dark. Statistical analysis showed the effective dose (ED50) values in the dark and light conditions were 8.6 and 4.2 µM, respectively. In addition, the results imply that in the range of 0-12 µM, the increase in the complex concentration correlates with the increase in the cytotoxicity effect. However, the cytotoxicity decreases at the higher concentration (50µM), which is likely due to aggregation of the complex. Conclusion: Our results show that Zn (II) tetrapyridinoporphyrazin complex may be a promising photosensitizer for innovative photodynamic therapy and may have a high potential application in cancer treatment. Furthermore, it seems to have more benefits compared to other known photosensitizers.