Aims: Investigations were carried out to observe the influence of winter/spring and summer periods on the survival of Salmonella typhimurium and indicator bacteria (psychrophilic, mesophilic, coliform and faecal coliform bacteria and faecal streptococci) in the solid fraction of pig slurry from agricultural wastewater treatment plant. Methods and Results: Leather squares and PVC bottles with openings served as test carriers. They were inoculated with broth culture of Salm. typhimurium and introduced directly into the solid fraction. During the experiment, quantitative and qualitative examinations were carried out to determine the presence of Salm. typhimurium and observe the dynamics of indicator bacteria in the solid fraction. Conclusions: Salmonella typhimurium survived for 26 d in summer and for 85 d in winter/ spring. The T-90 values of indicator bacteria in summer ranged from 35.44 d (coliform bacteria) up to 100.29 d (mesophilic bacteria). The winter T-90 values of indicator bacteria ranged from 74.58 d (faecal coliform bacteria) to 233.07 d (coliform bacteria). Significance and Impact of the Study: The present study demonstrated that it is necessary to pay increased attention to the manipulation of slurry solid fraction.