Four natural lactylates of chlorinated fatty acids, chlorosphaerolactylates A-D (1-4), were isolated from the methanolic extract of the cyanobacterium Sphaerospermopsis sp. LEGE 00249 through a combination of bioassay-guided and MS-guided approaches. Compounds 1-4 are esters of (mono-, di-, or tri)chlorinated lauric acid and lactic acid, whose structures were assigned on the basis of spectrometric and spectroscopic methods inclusive of 1D and 2D NMR experiments. High-resolution mass-spectrometry data sets also demonstrated the existence of other minor components that were identified as chlorosphaero(bis)lactylate analogues. The chlorosphaerolactylates were tested for potential antibacterial, antifungal, and antibiofilm properties using bacterial and fungal clinical isolates. Compounds 1-4 showed a weak inhibitory effect on the growth of Staphylococcus aureus S54F9 and Candida parapsilosis SMI416, as well as on the biofilm formation of coagulase-negative Staphylococcus hominis FI31.