<![CDATA[Low Birth Weight (LBW) is one of the factors that may increase the risk of growth and developmental problems in infants, including gross motor development. The age of 3–6 months is an important period for achieving gross motor milestones, making early detection of developmental delays necessary. This study aimed to analyze the relationship between low birth weight and gross motor development among infants aged 3–6 months in the working areas of Puhjarak and Ngancar Public Health Centers, Kediri Regency. This study employed a quantitative analytical design with a cross-sectional approach. The sample consisted of 72 infants aged 3–6 months selected using stratified random sampling. Birth weight data were obtained from the Maternal and Child Health (KIA) book, while gross motor development was assessed using the Pre-Screening Development Questionnaire (KPSP). Data were analyzed using the Chi-Square test with a significance level of α = 0.05. The results showed that among the 72 infants, 22 (30.6%) had a history of LBW and 50 (69.4%) had normal birth weight. Based on the assessment of gross motor development, 38 infants (52.8%) had development appropriate for their age, while 34 (47.2%) had development that was not appropriate for their age. The Chi-Square test showed a significant relationship between birth weight and gross motor development among infants aged 3–6 months (p = 0.018; α = 0.05). Infants with a history of LBW had a higher proportion of age-inappropriate gross motor development than infants with normal birth weight. These findings highlight the importance of developmental monitoring and early motor stimulation, particularly for infants with a history of LBW, as part of efforts to detect and address developmental problems at an early stage. ABSTRAK Berat Badan Lahir Rendah (BBLR) merupakan salah satu faktor yang dapat meningkatkan risiko gangguan tumbuh kembang bayi, termasuk perkembangan motorik kasar. Usia 3–6 bulan merupakan periode penting dalam pencapaian milestone motorik kasar sehingga deteksi dini terhadap kemungkinan keterlambatan perlu dilakukan. Penelitian ini bertujuan untuk menganalisis hubungan berat badan lahir rendah dengan perkembangan motorik kasar bayi usia 3–6 bulan di wilayah kerja Puskesmas Puhjarak dan Puskesmas Ngancar Kabupaten Kediri. Penelitian ini menggunakan desain kuantitatif analitik dengan pendekatan cross-sectional. Sampel penelitian berjumlah 72 bayi usia 3–6 bulan yang dipilih menggunakan teknik stratified random sampling. Data berat badan lahir diperoleh dari buku KIA, sedangkan perkembangan motorik kasar dinilai menggunakan Kuesioner Pra Skrining Perkembangan (KPSP). Analisis data dilakukan menggunakan uji Chi-Square dengan tingkat kemaknaan α = 0,05. Hasil penelitian menunjukkan bahwa dari 72 bayi, sebanyak 22 bayi (30,6%) memiliki riwayat BBLR dan 50 bayi (69,4%) memiliki berat badan lahir normal. Berdasarkan penilaian perkembangan motorik kasar, sebanyak 38 bayi (52,8%) memiliki perkembangan sesuai usia dan 34 bayi (47,2%) memiliki perkembangan tidak sesuai usia. Hasil uji Chi-Square menunjukkan terdapat hubungan yang signifikan antara berat badan lahir dengan perkembangan motorik kasar bayi usia 3–6 bulan (p = 0,018; α = 0,05). Bayi dengan riwayat BBLR memiliki proporsi perkembangan motorik kasar tidak sesuai usia yang lebih tinggi dibandingkan bayi dengan berat badan lahir normal. Temuan ini menunjukkan pentingnya pemantauan perkembangan dan pemberian stimulasi motorik secara dini, terutama pada bayi dengan riwayat BBLR, sebagai bagian dari upaya deteksi dan intervensi dini gangguan perkembangan]]>
