Filamentous fungi are important factories in the production and secretion of homologous and heterologous lignocellulolytic enzymes, however the regulation of protein secretion in these organisms need to be further explored. In order to investigate this regulation, Aspergillus nidulans recombinant strains were analyzed by transcriptomics. We designed three A. nidulans recombinant strains producing the following heterologous proteins: alpha-arabinofuranosidase (AbfA), beta-glucosidase (BglC) and thermophilic mannanase (1542). The heterologous genes abfA and bglC were highly expressed, while the levels of 1542 mRNA were similar to the reference gene. An indirect relationship between mRNA and the levels of protein secretion was observed, suggesting that transcription is not a bottleneck in these systems. Based on the general analysis of RNA-seq of the recombinant strains, it was possible to observe a predominant up-regulation response. Moreover, biological processes related to metabolism, protein with binding function and cellular transport were overrepresented. We also observed the unconventional splicing of hacA for the recombinant A. nidulansAbfA and A. nidulans1542, indicating some level of unfolded protein response. The global analysis showed mild stress at 2 h induction of heterologous protein production, which was normalized after 8 h. Our results provide insights to understand how A. nidulans adapts to the overproduction of heterologous proteins. Overall design: Transcriptional evaluation of three Aspergillus nidulans recombinant strains expressing heterologous proteins