A clinical isolate of *Candida parapsilosis* showed increased resistance to azole and echinocandin antifungals due to a mutation in the *ERG3* gene, which encodes a key enzyme in sterol biosynthesis. Transcriptome analysis revealed upregulation of genes involved in ergosterol biosynthesis, including *ERG2*, *ERG5*, *ERG6*, *ERG11*, *ERG24*, *ERG25*, and *UPC2*. Whole-genome sequencing identified a *G111R* mutation in *ERG3* in the resistant isolate, leading to reduced sterol desaturase activity. Replacement of the mutant *ERG3* alleles with the susceptible isolate's allele restored wild-type susceptibility to all tested azoles and echinocandins. Disruption of *ERG3* in both susceptible and resistant isolates resulted in loss of sterol desaturase activity, high-level azole resistance, and echinocandin-intermediate to -resistance. While *ERG3* disruption in *C. albicans* caused azole resistance, echinocandin minimum inhibitory concentrations (MICs) remained within the susceptible range. This study demonstrates that the *G111R* substitution in *Erg3* is responsible for the altered azole and echinocandin susceptibilities in the *C. parapsilosis* isolate and is the first report of an *ERG3* mutation influencing echinocandin susceptibility. The findings highlight the importance of *ERG3* in antifungal resistance mechanisms in *C. parapsilosis* and suggest that mutations in this gene may contribute to resistance to both azoles and echinocandins in this species.A clinical isolate of *Candida parapsilosis* showed increased resistance to azole and echinocandin antifungals due to a mutation in the *ERG3* gene, which encodes a key enzyme in sterol biosynthesis. Transcriptome analysis revealed upregulation of genes involved in ergosterol biosynthesis, including *ERG2*, *ERG5*, *ERG6*, *ERG11*, *ERG24*, *ERG25*, and *UPC2*. Whole-genome sequencing identified a *G111R* mutation in *ERG3* in the resistant isolate, leading to reduced sterol desaturase activity. Replacement of the mutant *ERG3* alleles with the susceptible isolate's allele restored wild-type susceptibility to all tested azoles and echinocandins. Disruption of *ERG3* in both susceptible and resistant isolates resulted in loss of sterol desaturase activity, high-level azole resistance, and echinocandin-intermediate to -resistance. While *ERG3* disruption in *C. albicans* caused azole resistance, echinocandin minimum inhibitory concentrations (MICs) remained within the susceptible range. This study demonstrates that the *G111R* substitution in *Erg3* is responsible for the altered azole and echinocandin susceptibilities in the *C. parapsilosis* isolate and is the first report of an *ERG3* mutation influencing echinocandin susceptibility. The findings highlight the importance of *ERG3* in antifungal resistance mechanisms in *C. parapsilosis* and suggest that mutations in this gene may contribute to resistance to both azoles and echinocandins in this species.