Background and Objective: Human flea is assumed as the most dominant ectoparasite associated with transmitting diseases via biting humans. Insecticides are widely employed to curb this vector. Assessment of susceptibility level of populations to various pesticides is necessary for taking appropriate control measures.

Materials and Methods: Subsequent to collection of human flee from indoor areas of Khodabandeh and Mahneshan located in Zanjan province from August 2013 to November 2014, they were kept under standard laboratory conditions. The samples were exposed to inconsistent doses of Permethrin and Lambdacyhalothrin and consequently their mortality rates were assessed after 24 hours.

Results: Out of 1074 collected fleas, 88.1% were Pulex irritans, 7.2% Ctenocephalides cani and 4.7% C. felis. Bioassay[s1]  results gave evidence to homogeneity of study population. LD₅₀ values for permethrin and lambdacyhalothrin were 288.40 – 295.15 µg/ cm² and 21.87 – 24.54 µg/cm^2, respectively.

Conclusion: High levels of LD₅₀ values to pyrethroides of human flea in the studied area indicated the requirement of more attention of health workers to control the vector and Further[s2]   research is necessary to assess the resistance status of human flea to alternative effective insecticides.