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<i>Peperomia obtusifolia</i> (L.) A. Dietr., native to Middle America, is an ornamental plant also traditionally used for its mild antimicrobial properties. Chemical investigation on the leaves of <i>P. obtusifolia</i> resulted in the isolation of two previously undescribed compounds, named peperomic ester (<b>1</b>) and peperoside (<b>2</b>), together with five known compounds, viz. <i>N</i>-[2-(3,4-dihydroxyphenyl)ethyl]-3,4-dihydroxybenzamide (<b>3</b>), becatamide (<b>4</b>), peperobtusin A (<b>5</b>), peperomin B (<b>6</b>), and arabinothalictoside (<b>7</b>). The structures of these compounds were elucidated by 1D and 2D NMR techniques and HREIMS analyses. Compounds <b>1</b>–<b>7</b> were evaluated for their anthelmintic (against <i>Caenorhabditis elegans</i>), antifungal (against <i>Botrytis cinerea, Septoria tritici and Phytophthora infestans</i>), antibacterial (against <i>Bacillus subtilis</i> and <i>Aliivibrio fischeri</i>), and antiproliferative (against PC-3 and HT-29 human cancer cell lines) activities. The known peperobtusin A (<b>5</b>) was the most active compound against the PC-3 cancer cell line with IC₅₀ values of 25.6 µM and 36.0 µM in MTT and CV assays, respectively. This compound also induced 90% inhibition of bacterial growth of the Gram-positive <i>B. subtilis</i> at a concentration of 100 µM. In addition, compound <b>3</b> showed anti-oomycotic activity against <i>P. infestans</i> with an inhibition value of 56% by using a concentration of 125 µM. However, no anthelmintic activity was observed.