Aim: The aim of the study was to assess parental knowledge about the development and care of a child aged 0–12 months as well as to verify whether this knowledge is sufficient to detect potential abnormalities and thus allow for early intervention. Another aim of the study was to determine the effects of selected sociodemographic characteristics of respondents on their knowledge about the development and care of a child aged up to 1 year. Material and methods: A total of 99 parents (82 women and 17 men) with children aged 0–12 months were included in the study. The study was conducted using an author’s online questionnaire. Two scales were the main dependent variables. One scale allowed for an assessment of respondents’ knowledge about child development, while the other scale verified the knowledge about childcare. The obtained data were analysed statistically using the IBM SPSS Statistics version 20. The analysis of contingency tables used percentage profiles and the Pearson Chi-square independence test as well as Cramér’s V association. The results were considered statistically significant at α = 0.05. Results: Statistical analysis of data points to an insufficient level of parental knowledge about the development and care of a small child. Factors such as education, place of residence and attending childbirth classes have a significant impact on this knowledge. Conclusions: Parental education on normal child development and childcare is necessary. This will help prevent many abnormalities by proper care as well as earlier detection of disorders and, consequently, early intervention.