The inspection of non-production cells of the RKP(b) in 1924–1925 was de facto purge of the Party, which affected a significant part of its members. It began soon after the end of the all-party discussion, in which L.D. Trotsky’s supporters were defeated, and became a method for fighting the opposition, which found much support in non-production cells. At the same time, the purge also was a kind of examination of qualitative composition of both examinees and their examiners. It revealed attitudes, relationships and progress of the local party work. The 1924–1925 event has not been sufficiently studied. This article aims to reconstruct the general picture of the purge on the basis of the verbatim reports of the plenums of the Central Control Commission of the RKP(b), as well as a number of other sources. The aspect of the struggle against the opposition found its greatest expression during the first stage of the purge in 1924, when “alien” elements were harshly excluded from the Party. Later, while this focus was retained, phenomena contrary to “party ethics” came to the fore, that is, drunkenness, embezzlement, performance of religious rites, moral decay, “passivity”, etc. The documents demonstrate the peculiarity of “centre-local” relations, when the local “check-up troikas”, disoriented by the ambiguity of instructions from the “centre”, tried to expel as many as possible members from the Party, while the higher bodies and the Central Control Commission were readmitting former Communists to the ranks of the RKP(b). The purge took place in an atmosphere of fear and often took on the character of a punitive action. It exposed the low level of political literacy of the majority of Party members, the heterogeneous social composition of the RKP(b), the impact of the New Economic Policy on the Communists, etc. The “check-up troikas” received a “mass of reports” on the party members, and during their “shocking” inspection work troikas did not always subject these allegations to thorough scrutiny, and in many cases dismissals were unfair. The inspection proved to be a kind of “mirror” of the party in the NEP period, and also revealed the serious problems which the party was inevitably going to have to face later.