Bacillus licheniformis I89 is a Gram‐positive bacterium, a producer of the lantibiotic lichenicidin. No information is available on its fatty acid (FA) composition. Bacillus species are rich in branched FA (BrFA), claimed to be beneficial to human health and to treat diseases. Herein, the FA profile of B. licheniformis I89 was evaluated under different growth conditions: at two growth temperatures (37 and 50 °C) and at different growth phases (lag, exponential, and stationary), using gas chromatography–mass spectrometry. The FA profile revealed predominant BrFA of the iso‐series and anteiso‐series (i‐15:0, ai‐15:0, i‐16:0, i‐17:0, and ai‐17:0) and low amounts of saturated FA (14:0, 16:0, and 18:0). Comparing the FA profiles at different temperatures, in the lag phase, at 50 °C, there was a decrease of ai‐17:0 and a decrease of i‐15:0 in the exponential phase, in comparison with 37 °C. In all growth phases, there was a decrease of ai‐15:0 and an increase of i‐17:0. From the lag to the stationary phase, at 50 °C, there was a decrease of ai‐17:0 and i‐16:0, whereas i‐15:0 increased, while at 37 °C, there was an increase of i‐15:0 and i‐16:0, and a decrease in ai‐15:0 and ai‐17:0. B. licheniformis I89 can adapt its FA profile, at moderate temperatures, by changing the iso‐FA and anteiso‐FA composition and the iso/anteiso ratio. This nonpathogenic bacterium species can be used as a source of BrFA with putative beneficial health effects for gut protection and with reported antitumor properties, foreseeing its use for producing compounds with biotechnological applications.