Cronartium ribicola, the causative agent of white pine blister rust is damaging to all five-needle pine species. Existing methods of treatment are largely ineffective, resulting in the need of more innovative approaches. Studies have shown that some conifer endophytes produce compounds that display potent antifungal activity, including towards haploid cultures of C. ribicola. Three conifer endophyte species were studied here. Compounds 1 – 4, (1’Z)-dechloromycorrhizin A (1), mycorrhizin A (2), chloromycorrhizin A (3) and the new natural product 3-chloro-4-[(1Z)-1’-chloroprop-1’-en-1’-yl]-9-hydroxy-8,8-dimethyl-9,4,5,8-tetrahydro-2H-1-benzopyran-5,2-dione (4) were isolated from L. papyraceum. Compounds 5 and 6 were produced by D. celastrina and were both identified as phomosolide A and a stable pyrone moiety of phomopsolide A respectively. The remaining compounds 2-(7-methoxy-2,5,6-trimethyl-4-oxo-4 H-benzo[d][1,3]dioxin-2-yl)propanoic acid (7), (E)-6-((3’-carboxybut-2’-en-2’-yl)oxy)-4-methoxy-2,3-dimethylbenzoic acid (8) and 2-(6-(hydroxymethyl)-7-methoxy-2,5-dimethyl-4-oxo-4H-benzo[d][1,3]dioxin-2-yl)propanoic acid (9) were isolated from S. foliicola and are novel metabolites. All compounds possessed antimicrobial activity in B. subtilis, E. coli, S. cerevisiae and M. violaceum assays.