Background It was reported that South Korea showed the greatest decline in the fertility rate among the entire OECD countries over the last 30 years with the total fertility rate (TFR) of 0.84 persons in 2020. Despite the efforts of the Korean government, the TFR has decreased constantly. This study intended to analyze the perception of Koreans toward pregnancy and childbirth regarding the low fertility rate in South Korea for understanding the causes of constantly decreased low fertility. Methods This study carried out an online survey based on 1,002 men and women aged 19 to 59 years old for six days from October 21 to October 26 in 2021 in cooperation with Gallup Korea. This study analyzed the perception of people toward low fertility, the severity of low fertility, and level of interest in low fertility to inspect awareness of the severity of low fertility in South Korea through a survey. Results It was found that 62%, 52%, and 72% of entire participants, women, and men agreed on a question “It is better to get married”. As for women’s age, a positive response for this question was derived from 34.2% (20s), 43.1% (30s), 53.4% (40s), and 71.4% (50s), respectively ( P < 0.001). In a question “the necessity of children”, a positive response for this question was derived from 34.7% (20s), 58.3% (30s), 75.9% (40s), and 83.5% (50s) of female respondents, respectively ( P < 0.001). Positive responses were shown 39.2%, 60.0%, 79.7%, and 81.5% of female participants in their 20s, 30s, 40s, and 50s agreed on the question “My children make me happy in my life”, respectively ( P < 0.001). Conclusion This study found that a decrease in the TFR was affected mainly by the negative perception of women in their 20s and 30s toward marriage, childbirth, and the necessity of children. Therefore, further research should be conducted to develop policies that focus on these significant variables to overcome the worsening low fertility problem.