This study aimed to elucidate the role of smell diaries in Olfactory training (OT) and probe gender differences in intensity ratings and measured olfactory function throughout the OT course. Fifty olfactory loss patients (36 women and 14 men) undergoing OT rated odor intensities on a daily basis for at least 12 weeks. They exhibited significant improvement in measured olfactory function after OT; gender had no significant effect. As for the diaries, women rated odors with higher intensities than men, and ratings from women increased with time while men rated odors at the same level. Across all patients, there was a weak positive correlation between ratings and psychophysical test scores (r = 0.30, p =.04). Throughout the OT course, the increase in odor intensity ratings was more pronounced in women than it was in men (F[1, 44] = 7.9, p =.007). However, this gender-related difference was not found for measured olfactory function, suggesting pronounced gender-differentiated behaviors in terms of self-ratings of olfactory function. Practical Applications: OT is often used for the rehabilitation of olfactory loss, and a smell diary is suggested to document the perceived odor intensity. The patients can benefit from this rating procedure by surveying the olfactory change, predicting their OT outcomes, and motivating them to maintain training. Our study provides evidence that each gender rates odor intensity in different ways; therefore, the rating scores should be interpreted correspondingly. It also implied that women among well-trained sensory panelists (e.g., for food quality control) could rate the intensity of stimuli higher than men in the same panel. The rating bias arising from gender should be taken into consideration when it comes to professional sensory evaluation.