An experiment was conducted to evaluate the effect of a low-pathogenic H6N2 avian influenza A viral strain (LPAIV strain H6N2) on subsequent (after 3 days) vaccination with a lentogenic avian paramyxovirus serotype 1 strain La Sota (APMV-1 strain La Sota) in guinea fowl. The effects were monitored by detection of the presence of viruses in cloacal and oropharyngeal samples, as well as by the presence of humoral immune response. The obtained results were compared to birds with monoinfections. Replication and virus shedding of LPAIV strain H6N2 from the cloaca and the oropharynx were established, while APMV-1 La Sota was reisolated only from the oropharynx. The reisolation of LPAIV strain H6N2 was similar in both monoinfection and co-infection. The dynamics of virus replication of APMV-1 strain La Sota was affected in the beginning of the co-infection, later occurrence of the peak which matched the period of decline of LPAIV strain H6N2 reisolates. The LPAIV strain H6N2 and APMV-1 strain La Sota co-infection did not exert any influence on humoral immune response to both viruses.