BACKGROUND: We prospectively evaluated the performance of blood culture resin media, FA Plus and FN Plus, of the BacT/Alert 3D System (bioMérieux Inc., USA) in a tertiary university-affiliated hospital. METHODS: We obtained 2,994 blood culture sets. The positivity and time to detection (TTD) were compared between FA Plus and FN Plus for clinically significant microorganisms. We then categorized patients into two groups based on antibiotic treatment before blood culture to observe the difference of positivity between two groups. RESULTS: Among 2,994 sets received, 371 (12.4%) yielded 385 clinically significant pathogens. Comparing FA Plus to FN Plus media, lactose non-fermenters (18 vs. 1; P<0.001) and yeasts (15 vs. 0; P<0.001) were recovered at a significantly higher rate using FA Plus, whereas gram-positive cocci (10 vs. 26; P=0.011) and gram-negative anaerobes (0 vs. 10 P=0.002) were isolated at a higher rate using FN Plus. In terms of detection time in FA Plus compared to that in FN Plus, Staphylococcus aureus (13.8 hr vs. 18.1 hr) and gram-positive cocci (14.1 hr vs. 20.3 hr) were detected significantly earlier in FA Plus (each, P<0.001). There was no statistically significant difference in positivity based on prior antibiotic use (13.1%, 65/498) compared to antibiotic naïve patients (12.3%, 306/2,496) (P>0.05). CONCLUSIONS: Complementary detection of microorganisms was observed between FA Plus and FN Plus. Gram-positive cocci including S. aureus grew faster in FA Plus. In addition, the rate of positivity was not affected by prior antibiotic therapy in BacT/Alert 3D resin media.