<p>This study investigated the presence and diversity of fungal species in wastewater and sediment from open drainage systems along the Ntanwogba Creek in Port Harcourt, Nigeria. Open drains, often clogged with household waste due to poor sanitation, pose significant environmental and public health risks—especially during rainfall when runoff spreads contaminants. Wastewater and sediment samples were collected from five sites and analyzed using standard microbiological techniques. Total fungal counts ranged from 4.3×10⁵ to 1.7×10⁶ cfu/mL in wastewater and from 5.7×10⁴ to 2.9×10⁶ cfu/g in sediment. A total of 77 fungal isolates were identified, with Cryptococcus neoformans (36.4%) and Rhizopus spp. (29.9%) being the most prevalent. Other species included Torulopsis glabrata (10.4%), Penicillium chrysogenum (7.8%), Aspergillus versicolor (5.2%), and Aspergillus niger (3.9%), while Mucor, Aspergillus tamarii, Scopulariopsis, and Phoma each accounted for 1.3%. Yeast species from the genera Torulopsis and Cryptococcus were also isolated. The presence of opportunistic fungal pathogens in open drainage suggests potential health risks to nearby communities, as well as their ecological role in nutrient cycling.</p>