* AwesomeMusic: Most of the show's composers. JerryGoldsmith did the show's theme (and three episode scores). See also [[Series/HawaiiFiveO Morton Stevens]].
* BadassDecay: Heroes Napoleon Solo and Illya Kuryakin are sometimes subject to plot dependent BadassDecay, when necessary. E.g., in the third act of the third season episode, "The Five Daughters Affair, Part II", Solo and Kuryakin fight THRUSH's "karate killers" ([[spoiler:who despite that name (as given in the credits) do very little actual killing in the episode]]) for about the sixth time in this two-part adventure. Despite holding their own in several earlier fights with the karate killers, in this scene Solo and Kuryakin completely lose whatever fighting skills they've demonstrated earlier, and are straightaway handed their asses by the THRUSH "killers" in mere seconds. This is necessary, of course, to set up the fourth act's climax and resolution (therefore "plot dependent").
* CompleteMonster: Season 3's "Five Daughters Affair" two-parter (later released in theaters as ''The Karate Killers'') has [[NebulousEvilOrganization THRUSH]] agent Randolph, whose plot involves releasing seawater-derived gold onto the market in order to create massive profits for THRUSH. His actions include seducing the wife of the doctor who created the method then killing her [[YouHaveOutlivedYourUsefulness once he has no more use for her]], gleefully taunting her before murdering her; poisoning the doctor; attempting to [[OffWithHisHead behead]] Illya in an ice-chopping machine; [[WouldHitAGirl smacking around Sandy]]; and shooting an unarmed elderly man [[DisproportionateRetribution just for raising his voice to him]]. These acts, coupled with his general SmugSnake demeanor, cement Randolph as probably the seriesís nastiest villain.
* EnsembleDarkhorse: Illya Kuryakin.
* EstrogenBrigade: Coalesced around Illya Kuryakin/David [=McCallum=].
* FairForItsDay: Illya Kuryakin is not only a Russian, but a Soviet patriot and ''a commissioned officer in the Red Navy'' (at one point, he even appears in Soviet naval uniform). Still, he is never portrayed as anything other than a trustworthy ally and decent man. Not bad for a series first broadcast in 1964.
** "The Project Strigas Affair", which featured Creator/WilliamShatner and Creator/LeonardNimoy in their first appearance together, two years before ''Series/StarTrekTheOriginalSeries''. And to make it extra funny, Nimoy's character is repeatedly derided as a "fool."
** The innocent in "The Never-Never Affair" is an U.N.C.L.E. translator played by Barbara Feldon; this episode premiered a few months before she got a transfer and a promotion (to [[Series/GetSmart Agent 99]]).
-->'''Illya Kuryakin:''' [''to Solo''] You just like blondes.
-->[''Solo raises his eyebrows suggestively'']
-->--"The Girls of Nazarone Affair" [Season 1]
** Every now and then, there's a gag on how Napoleon lost the girl but not Illya. "At least we still have each other."
** "The Cherry Blossom Affair": "I'd like to hear your story. Any time." And then Illya puts his hand behind his head as if to pose and Napoleon scowls.
** In "The Virtue Affair", at a threat to Napoleon, Illya's lower lip actually wibbles before he gives up to save Solo's life.
* NightmareFuel: Solo's interrogation in "The Summit-Five Affair".
* TheyWastedAPerfectlyGoodPlot: "The Hula Doll Affair" features two brothers who happen to be rival THRUSH executives in a plot involving the title doll, which has a heat-sensitive explosive inside, and Napoleon impersonating a delegate from THRUSH Central. A recipe for power plays and suspense? It likely would be had it not been in [[SeasonalRot season three]] and scripted by Stanford Sherman, who also did the one with Illya riding a bomb filled with essence of skunk ("The Super-Colossal Affair") and the one with popsicle bombs aimed at Victor Borge ("The Suburbia Affair"). Throw in the executives being played by Jan Murray and Pat Harrington, and their mother [[spoiler: and real THRUSH Central member]] being played by perennial LargeHam Patsy Kelly, and... oh dear.