Background: Recent studies have shown a decline in birth rates in large metropolitan areas (after accounting for population), which can be possibly explained by barriers to reproduction associated with the COVID-19 pandemic and related lockdowns. Objective: This study’s objective was to investigate the impact of the COVID-19 pandemic and related lockdowns on the fertility rates of women in reproductive ages living in Greater Phoenix. Methods: The total number of inpatient births and people in both Maricopa and Pinal Counties during pre-COVID-19 years (2017-2019) were compared with those during the COVID-19 years (2021) among women in reproductive ages (15-49 years). To make age-specific comparisons, women in reproductive years were divided into eight distinct age group categories (15-17, 18-20, and then five year age group categories to age 49) from which age-specific, general, and total fertility rates were calculated. Results: Using a two-sample z-test for difference in proportions, findings revealed that the general fertility rate in Greater Phoenix had significantly declined from 48 to 46 per 1,000 population from the pre-COVID-19 period to COVID-19 period (P<0.001). Two sample z-tests were also used to compare age-specific fertility rates, which revealed a significant decline in the fertility rate in women ages 15-17 (from 8.0/1000 to 5.0/1000) (P<0.001), 18-20 (from 43.0/1000 to 35.0/1000) (P<0.001), and 21-24 (from 79.0/1000 to 68.0/1000) (P<0.001) from the pre-COVID-19 period to COVID-19 period, while no significant change was observed in the fertility rate in women ages 25-49. Conclusions: The observed general fertility decline in Greater Phoenix as a result of the COVID-19 pandemic poses significant implications for further research on barriers to reproduction brought upon by the COVID-19 pandemic and related lockdown measures. Another direction for further research involves possibly continuing this study to include years 2022 and 2023 in the COVID-19 period, as well as calculating age-specific fertility rates by race.