Pineapple (Ananas comosus (L.) Merr.) is a tropical fruit plant from the Bromeliaceae family. Pineapple has high heterozygosity even though it is cultivated vegetatively, so the unique characteristics of the Ananas species need to be studied cytologically. The aim of this study were: (1) To obtain genetic information on the number, size, and shape of chromosomes, as well as the chromosome arrangement of pineapple plants; (2) To determine the karyotype pattern arrangement in pineapple plants; (3) Comparing chromosome structures between pineapple varieties to reveal indications of phylogenetic relationships between varieties within a species. The method used was squashing. This research was conducted at the Plant Breeding Laboratory, Faculty of Agriculture, UNS from December 2024 to June 2025. The plant parts used as research materials were pineapple roots tip grown from crowns via water propagation. Observation variables were number of chromosome, size of chromosome, shape of chromosome, karyotype, and chromosomal asymmetry index. Each variety was studied using four replications, and data analysis was conducted descriptively. The results showed that pineapple and red wild pineapple chromosomes have the same number of chromosomes, namely 50 chromosomes (2n=50), with an average chromosome arm length of 0.895±0.211 µm for pineapple (var. comosus) and 0.723±0.126 µm for red wild pineapple (var. bracteatus). All chromosomes were metacentric with a karyotype formula of 2n=2x=50=25m. The Intrachromosomal Asymmetry Index (A1) and Interchromosomal Asymmetry Index (A2) showed small values, indicating that both species are composed of metacentric chromosomes with minimal size variations.Pineapple (Ananas comosus (L.) Merr.) is a tropical fruit plant from the Bromeliaceae family. Pineapple has high heterozygosity even though it is cultivated vegetatively, so the unique characteristics of the Ananas species need to be studied cytologically. The aim of this study were: (1) To obtain genetic information on the number, size, and shape of chromosomes, as well as the chromosome arrangement of pineapple plants; (2) To determine the karyotype pattern arrangement in pineapple plants; (3) Comparing chromosome structures between pineapple varieties to reveal indications of phylogenetic relationships between varieties within a species. The method used was squashing. This research was conducted at the Plant Breeding Laboratory, Faculty of Agriculture, UNS from December 2024 to June 2025. The plant parts used as research materials were pineapple roots tip grown from crowns via water propagation. Observation variables were number of chromosome, size of chromosome, shape of chromosome, karyotype, and chromosomal asymmetry index. Each variety was studied using four replications, and data analysis was conducted descriptively. The results showed that pineapple and red wild pineapple chromosomes have the same number of chromosomes, namely 50 chromosomes (2n=50), with an average chromosome arm length of 0.895±0.211 µm for pineapple (var. comosus) and 0.723±0.126 µm for red wild pineapple (var. bracteatus). All chromosomes were metacentric with a karyotype formula of 2n=2x=50=25m. The Intrachromosomal Asymmetry Index (A1) and Interchromosomal Asymmetry Index (A2) showed small values, indicating that both species are composed of metacentric chromosomes with minimal size variations.Keywords: Bromeliaceae; cytology; karyotype; root tip; squash method.