Background: In 2016, FDA recommended that "serious side effects associated with flouroquinolones generally outweigh the benefits for the patients with acute sinusitis, acute bronchitis and uncomplicated UTI". Throughout India the most commonly used flouroquinolones for above conditions are Ciprofloxacin, Ofloxacin, and Levofloxacin. In this scenario, the present study was undertaken to monitor, evaluate and compare the adverse effect profile of Ciprofloxacin and Ofloxacin in acute exacerbation of chronic bronchitis patients. Methods: Prospective, observational study done in 200 patients of tertiary care teaching hospital. The patients diagnosed with, acute bronchitis treated with Ciprofloxacin 500mg BD or Ofloxacin 400mg BD for 7 days were included in the study. The study duration was 6 months. ADR causality assessment was done with Naranjo algorithm. Statistical test applied was chi-square test. Results: 63 ADR were reported in Ofloxacin group and 19 ADR in Ciprofloxacin group. Insomnia was most frequent ADR (40%) in patients treated with Ofloxacin. There is high incidence of ADRs in ofloxacin group. chi square test showed this difference is statistically significant (p<0.05). Insomnia was significantly higher in ofloxacin group (p<0.05). Conclusions: In India frequently used and misused antimicrobials are fluoroquinolones. The present study concluded that no serious ADRs but ofloxacin group of patients have shown increased incidence of ADRs associated with CNS especially Insomnia. However, further large scale, multi-centric studies are needed to confirm these results.