Aim: In real life, we aimed to evaluate the effect of new generation insulin glargine u-300 on fasting blood glucose, HbA1c, LDL and triglyceride levels. Material and Methods: This is a retrocspective cohort study. We retrospectively reviewed patients who applied to the Endocrinology and metabolism outpatient clinic of Eskişehir Osmangazi University in 2019, whose old generation basal insulin was replaced with glargine u-300 and whose antilipidemic treatment was not changed. We compared fasting blood glucose(mg/dl), HbA1c(%), LDL(mg/ dl) and triglyceride(mg/dl) values at baseline and after 3 months. We also evaluated these data by separating them into genders. Shapiro– Wilk normality test was performed for continuous variables. Wilcoxon Signed Ranks test was performed for non-normally distributed variables. Results: Data concerning 109 patients were analysed. The fasting blood glucose average and median value decreased in control after starting glarjin u-300. However, it was not statistically different (p=0.06). The HbA1c control value (8.8%) decreased statistically significantly compared to the baseline value (9.61%) (p<0.001). The LDL control value(116.6mg/dl) also decreased statistically significantly compared to the baseline value (124mg/dl) (p<0.001). Although Hba1c and LDL were significant, there was no significant difference in terms of triglycerides. When we evaluate the sexes separately, we see that fasting blood glucose, HbA1c, LDL and triglyceride values decrease more in men. Fasting blood glucose, which does not show statistically significant difference in women, has been shown to decrease significantly in men. Conclusion: We think that showing statistically significant HbA1c and LDL decline with the Glarjin u-300 in real-life data is promising for further studies. At the same time, despite the significant decrease in fasting blood glucose in men, the inability to show it in women should be considered as data that need further evaluation.