e17006 Background: External beam radiotherapy combined with intracavitary brachytherapy is the standard of care in Carcinoma cervix. Due to its characteristics of rapid dose fall off, brachytherapy limits the toxicity to organs at risk while escalating radiation dose to target. Still, the organs near the radioactive source are at risk of considerable exposure, toxicity and post treatment morbidity. Alteration of bladder volume, alters the relative anatomy of uterus, rectum, sigmoid colon causing changes in the radiation dose to these organs. Methods: Aim:To correlate between the bladder volume and its effects on the dose received by bladder, rectum and sigmoid colon in volume based HDR brachytherapy in carcinoma cervix.30 patients (78 Intracavitary Brachytherapy applications) of Carcinoma Cervix (FIGO stage II-III) treated with EBRT followed by volume based HDR brachytherapy at our institute between July 2014 to Jan 2016 were studied. Bladder volume data was tabulated into five groups according to increasing volume of bladder. It was correlated with D2cc dose received by bladder, rectum and sigmoid colon. Results: Statistical Analysis Linear regression and correlation analysisof the HRCTV with dose to the bladder was 0.2 (.i.e HRCTV does not influence the bladder dose.) Pearson correlation of bladder volume and D2cc bladder and D2cc rectum was positive for all groups and for sigmoid D2cc was positive for group B and negative for all other groups. P value = 0.064 Conclusions: Keeping the bladder volume low (<130 cc) during brachytherapy would reduce the dose to bladder and rectum and the probability of late bladder and rectal toxicity reduces. [Table: see text]