Metal coordination compounds have an important role in the development of novel drugs. Using the resazurin microtitration assay we assessed the cytotoxicity and antiviral activity of the ligand 2-(diphenylphosphino)benzaldehyde 1-adamantoylhydrazone and its Pd(II) and Pt(II) complexes. Cytotoxicity was tested in A549 human lung adenocarcinoma epithelial cells. We observed that the ligand displayed a more pronounced cytotoxic activity than the platinum-based drug, carboplatin. Morphological evaluation of A549 cells treated with the ligand by acridine orange and ethidium bromide double staining revealed the presence of signs of apoptosis. Antiviral activity against poliovirus type 1 was assessed by examination of the cytopathic effect (CPE) in Hep-2 cells. Cells that were exposed to the 19 μM ligand before infection displayed a maximal significant reduction (by 24.42 ± 1.49%) of the CPE. This was likely due to the inhibition of virus receptors and prevention of viral adsorption. Treatment with 17 μM Pt(II) complex after viral infection caused a maximal significant reduction (by 30.52 ± 3.12%) of the CPE, presumably through an effect on viral replication. The results indicate that the ligand should be viewed as a potential anticancer agent. The ligand and the Pt(II) complex show promising results for further investigation of antiviral activity.