The pp → ppφ reaction has been studied at the Cooler Synchrotron COSY-Jülich, using the internal beam and ANKE facility. Total cross sections have been determined at three excess energies ǫ near the production threshold. The differential cross section closest to threshold at ǫ = 18.5 MeV exhibits a clear S-wave dominance as well as a noticeable effect due to the proton-proton final state interaction. Taken together with data for ppω-production, a significant enhancement of the φ/ω ratio of a factor 8 is found compared to predictions based on the Okubo-Zweig-Iizuka rule.PACS numbers: 25.10.+s, 13.75.-n Meson production near threshold has the potential to clarify important questions of hadron physics in the nonperturbative regime of quantum chromodynamics due to its comparatively simple scheme of interpretation. The production of light vector mesons, ρ(770), ω(782) and φ(1020), quark anti-quark states with their spins aligned (J P =1 − ) and without open strangeness, has been investigated with both hadronic and electromagnetic probes in order to study production mechanisms [1], coupling constants [1], modifications in nuclear medium [2] and in particular the so-called Okubo-Zweig-Iizuka (OZI) rule [3]. This rule states that processes with disconnected quark lines between initial and final states are suppressed compared to those where the incident quarks continue through to the exit channel. As a result, the production of ideally mixed φ-mesons (quark content ss) in a reaction A + B → φX is reduced compared to A + B → ωX (ω is a linear combination of uū + dd) under similar kinematical conditions. Taking into account deviations from ideal mixing between singlet and octet vector mesons, Lipkin predicted a ratio of single φ to ω production of R φ/ω = 4.2 × 10 −3 ≡ R OZI [4,5]. However, strong enhancements of the experimental R φ/ω compared to R OZI have been observed (an overview is given in Ref.[6]), in particular inpp annihilations, where R φ/ω can be as large as ∼ 100×R OZI [7]. Here a strong correlation of the φ meson yield with the spin-triplet fraction of the initial state was found [8], and this in part motivated the suggestion of a polarized internal strangeness component in a polarized nucleon [9]. However, alternative explanations, such as two-step kaon-exchange models [10,11], have also been advanced. Since vector-meson production in close-to-threshold pp → ppV reactions must proceed via the spin-triplet entrance channel, the investigation of the cross section ratio σ(pp → ppφ)/σ(pp → ppω) at small excess energies ǫ should provide a clean way of investigating possible violations of the OZI rule.Total cross sections for ω-production in proton-proton collisions have been measured in a range of excess-energy ǫ from a few MeV up to several GeV [12,13,14], whereas data for ppφ are very scarce. Two total cross sections of φ production have been obtained for ǫ ∼ (2 − 4) GeV, but with rather limited accuracy [15,16]. At low excess energy, a single measurement of total and differential cross sections has been made b...