The objective of the study was to uncover the developmental dynamics in Bacillus subtilis biofilms on a transcriptome level. The experiment covered a developmental timeline over two months of biofilm growth. Overall design: Bacterial biofilms were sampled during a development period of two months. The experimental period was covered with 11 sampling points starting from a liquid bacterial culture 24h after inoculation followed by biofilm cultures harvested from a solid MSgg agar plate at 6h, 12h, 1 day, 2 days, 3 days, 5 days, 7 days, 14 days, 1 month and 2 months after inoculation. Each sample was represented in three replicates, except the 2M samples which was represented by a single replicate.