Introduction and Objectives: Laboratory testing is very important for diagnosing a disease, monitoring its progress and to monitor the response in patients to treatment. This study analyses the effects of reinforcing skill training among the laboratory personnel on the frequently occurring pre-analytical errors in clinical biochemistry samples. Materials And Methods: Retrospective analysis of biochemistry laboratory records, of a tertiary care hospital, between two time points, i.e., April - October 2016 (7 months) and April- October 2017 (7 months) were compared. The laboratory personnel had undergone reinforcement training in between the two phases. Data analysis was done by using Epi-info Software version 3.4.3. Frequencies and percentages, which are part of descriptive statistics, were calculated. Results: We received a total of 2, 77,438 patient samples (1, 30, 647 samples in 2016 and 1, 46,791 samples in 2017) for a period of 14 months. For the year 2016, the total number of pre-analytical errors was 1,215 (0.93%) and for the year 2017 it was 1,110 (0.76%). Based on the occurrence of the pre-analytical errors, the order recorded was: - haemolysis (77%), insufficient quantity of sample (8%), errors during sample transport (6%), errors during specimen handling (5%), and wrong tube collection (4%). Conclusion: In order to safeguard patient interest and improve as well as ensure proper medical and testing services to patients we have to maintain proper quality control in all the phases of analysis and take efforts to reinforce and improve the skills of the laboratory personnel, especially in the pre-analytical phase. For achieving this, regular audits and proper monitoring is necessary. Keywords: Pre-analytical errors, Turnaround time (TAT), Total testing process (TTP), India.