The present study was conducted to estimate the mineral elements and to determine antimicrobial and radical scavenging efficacy of flower of Lagerstroemia speciosa (L.) belonging to the family Lythraceae. Estimation of mineral elements present in microwave digested sample of flower was done by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Antimicrobial activity of methanol extract of flower was determined against 5 isolates of Streptococcus mutans, 5 isolates of Staphylococcus aureus, Candida albicans and Cryptococcus neoformans by Agar well diffusion assay. Radical scavenging activity was performed by ABTS radical scavenging assay. The content of potassium and sodium was highest and least among major elements respectively. In case of minor elements, content of iron was highest whereas the content of nickel was least. The extract was effective in inhibiting all test microorganisms. Among bacteria, high susceptibility was observed in case of S. aureus isolates. C. neoformans was inhibited to high extent than C. albicans. The extract scavenged ABTS radicals in a dose dependent manner. The flower of L. speciosa can be used as a source of various mineral elements having key role in the normal physiology of an individual. The flower may also be used against diseases caused by infectious agents and oxidative damage caused by free radicals.