Highly anisotropic particles of Tl-1212, Tl-2212, Tl-1223 and Tl-2223 superconductors were grown. The Tl-free precursor powders with the compositions Ba{sub 1}Ca{sub 2}Cu{sub 3}Ag{sub 0.37}O{sub 6} and Ba{sub 2}Ca{sub 2}Cu{sub 3}Ag{sub 0.37}O{sub 7} were prepared using an aerosol flow reactor. These precursor powders were then post-annealed in 0.1 atm oxygen at 700 C for 4h to reduce the carbon present and mixed with Tl{sub 2}O{sub 3} (typical composition of Tl{sub x}; x = 0.6--1.0). The Tl-containing powders were heated in sealed gold tubes between 650--890 C for various times. X-ray diffraction showed that the Tl-2212 and Tl-2223 phases were stable over a wide range of temperatures. Scanning electron microscopy showed evidence for the presence of high aspect-ratio particles. These highly anisotropic particles may be of interest for the preparation of powder-in-tube and other powder deposited conductors, for current leads, and for grain alignment studies.