Test crosses of 21 germplasms of Brassica napus with two CMS lines (Z1 and Z2) were done for identification of maintainer lines. The test cross progenies were grown in the research field, Department of Genetics and Plant Breeding, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur during winter season. The test cross results indicated that there was a wide variation among the genotypes in respect of flowering characters along with yield and yield attributes. Anther and stamen of pollen parents were larger as compare to CMS line and its test cross progenies. In case of CMSZ1 and CMSZ2 first flower opened at 36.67 and 32.33 days after sowing, respectively. The genotypes Nap206, Nap205, Nap2037 and Nap9904 were identified as effective maintainer for CMSZ1 and Nap206, Nap108, Nap205, Nap9908, Nap9905, Nap9904 and BARI Sarisha-8 for CMSZ2 as they produced 100 percent male sterile progeny in full sib generation. From the investigation, it was observed that all the male sterile progenies produced small and slender anther with short filament as well as the smallest stamen.