Abstract: The objective of current paper was to in vitro screen the set of ortho-/meta-/para-alkoxyphenylcarbamic acid esters bearing 4-(4- fluorophenyl)piperazin-1-yl moiety for their potency against avirulent Mycobacterium tuberculosis H37Ra by applying the micromethod for the determination of the minimum inhibitory concentration (MIC). Considered mycobacterial strain was grown in Middlebrook broth, supplemented with Oleic-Albumin-Dextrose-Catalase supplement and mycobactin J (2 µg/mL) as well. The susceptibility of the strain was investigated in a 96-well plate format, the plates were incubated at 37°C for 7 days. Following estimated MIC readouts, it was suggested that meta-/para-alkoxy substitution within lipophilic fragment would be favorable for the activity of currently investigated compounds against given mycobacterium compared to the ortho-position of attached alkoxy side chain. From the entire set, para-propoxy substituted derivative was considered the most effective with the estimated MIC=62.5 µg/mL (0.13 mmol/L).