The objective of this study was to develop an index to assess the management applied to dairy cows during transition period, known as Transition Cow Index (TCI), using information from official DHIA Paraná herds, Southern Brazil. Data set was assigned by Holstein Cattle Breeders Association from Paraná State (APCBRH) and it had originally 310,007 first monthly test-days collected between 5 and 40 d after calving from 2000 to 2013. To generate this index several information from previous lactation were used. First-lactation data were excluded and animals were categorized in 2nd, 3rd, 4th, and 5th lactation or more. After editing, only Holstein data were kept in the final data set, which had 94,508 first test-days from 445 herds. Pearson correlations among independent variables and milk yield on first test-day were estimated by CORR procedure from SAS. Previous cumulative milk yield was the variable with the highest correlation with the first test-day milk yield (r = 0.42). Previous cumulative milk yield, DIM in prior lactation (linear and quadratic effects), linear somatic cell score at the last test-day of previous lactation, days dry (linear and quadratic effects), lactation number, month of calving, milking frequency and DIM at first test were the independent variables used in GLM procedure from SAS to generate an expected milk yield in the first test-day after calving. The expected daily production was compared with the actual production collected, to generate TCI in kg/d. During the whole period investigated, 50.9% of the analyzed data had positive TCI (above expectations) and 49.1% had negative TCI (below expectations) and the overall TCI average was −0.283 kg/d. The 5 best herds with 100 or more test-days had TCI average of 3.908 kg/d and the 5 worst herds with 100 or more test-days had TCI average of −5.589 kg/d. Transition Cow Index proved to be an efficient tool for evaluation of transition period management of Paraná herds. It is recommended to not overlook individual cows that fail and to use TCI only at herd level.