Latar belakang. Dengue yang merupakan penyakit infeksi endemik di Indonesia dengan incidence rate yang terus meningkat sejak tahun 1968 tidak hanya merugikan masyarakat dari segi kesehatan, namun juga dari segi ekonomi. Belum ada penelitian mengenai persentase limfosit sebagai faktor prediktor durasi rawat inap pasien dengue yang akan berpengaruh terhadap beban ekonomi. Tujuan penelitian. Penelitian ini ingin mengetahui apakah adanya hubungan antara persentase limfosit saat masuk rumah sakit dengan durasi rawat inap pada pasien anak infeksi virus dengue di RS Siloam Lippo Village. Metode penelitian. Penelitian ini akan menggunakan 182 data rekam medis pasien anak infeksi virus dengue dari RS Siloam Lippo Village dari tahun 2017 hingga 2021, dan akan dianalisis secara univariat menggunakan uji Kolmogorov- Smirnov serta secara bivariat menggunakan uji Spearman. Hasil. Uji Kolmogorov-Smirnov menunjukkan hasil distribusi data yang tidak normal (p=0,000) dan uji Spearman menunjukkan bahwa persentase limfosit memiliki hubungan yang signifikan terhadap durasi rawat inap pasien anak infeksi dengue (r=-0,663, p=0,000) dengan kekuatan korelasi kuat dan berarah negatif. Nilai median persentase limfosit sebesar 33,50 ± 25% dan durasi rawat inap selama 5 ± 2 hari. Kesimpulan. Terdapat hubungan antara persentase limfosit saat masuk rumah sakit dengan durasi rawat inap pada pasien anak infeksi virus dengue di RS Siloam Lippo Village. Kata kunci: Dengue, demam berdarah, persentase limfosit, durasi rawat inap, pasien anak, infeksi. / Background. Dengue, which is an endemic infectious disease in Indonesia with an increasing incidence rate since 1968, is not only detrimental to the community in terms of health, but also from an economic perspective. There has been no research on the percentage of lymphocytes as a predictor of the duration of hospitalization for dengue patients which will affect the economic burden. Research objectives. This study aims to determine whether there is a correlation between the percentage of lymphocytes on complete peripheral blood examination at the time of hospital admission and the duration of hospitalization in pediatric patients with dengue virus infection at Siloam Hospital Lippo Village. Research methods. This study will use 182 datas on pediatric patients with dengue virus infection from Siloam Hospital Lippo Village from 2017 to 2021, and will be analyzed univariately using the Kolmogorov-Smirnov test and bivariately using the Spearman test. Results. The Kolmogorov-Smirnov test showed that the data distribution was not normal (p=0.000) and the Spearman test showed that the percentage of lymphocytes had a significant relationship with the duration of hospitalization for pediatric dengue infection patients (r=-0.663, p=0.000) with a strong correlation strength and a negative trend. The median value of lymphocyte percentage was 33.50 ± 25% and the duration of hospitalization was 5 ± 2 days. Conclusion. There is a relationship between the percentage of lymphocytes on admission to the hospital and the duration of hospitalization in pediatric patients with dengue virus infection at Siloam Hospital Lippo Village. Keywords: Dengue, dengue fever, lymphocyte percentage, duration of hospitalization, pediatric patients, infection.